Defending champion Jimmy White has been drawn again three-time World Championship semi-finalist Tony Knowles in the first round of the 2021 World Seniors.
Knowles, 65, famously defeated defending champion Steve Davis 10-1 in the opening round of the 1982 World Championships.
The Boltonian went on to make the last four at the Crucible in 1983, 1985 and 1986.
White, 58, claimed his first World Seniors title in 2019 and followed that up last season with a dramatic 5-4 victory over Ken Doherty in the final to defend his crown.
He will be looking to make it three titles in a row when the World Seniors Championship returns to the Crucible in Sheffield from 6-9 May.
There are five former world champions in this year's draw - Doherty, Stephen Hendry, John Parrott, Dennis Taylor and Joe Johnson.
BBC Sport will have full coverage of the tournament on Red Button, iPlayer and online.
Murphy & Selby through to second round
Getty ImagesCopyright: Getty Images
Shaun Murphy fought back from 5-3 down to secure his place in the last 16 with a 10-7 win over over Mark Davis.
Davis, 48, was making his 12th appearance at snooker's showpiece event and outplayed the out-of-sorts 2005 champion in the opening session.
But Murphy, buoyed by a century in the final frame, reduced the gap to 5-4 and was much improved on the resumption.
Breaks of 56 and 92 and helped him win four of the next five frames for an 8-6 lead and, after sharing the next two, the world seven number got over the line with stunning 131.
Three-time champion Mark Selby joined Murphy in the second round with a devastating 10-1 demolition of qualifier Kurt Maflin.
Selby, 37, needed just two frames to progress having scored two tons and six further breaks of more than 50 in a one-sided opening session against a player who reached the Crucible quarter-finals last season.
And the Leicester potter wasted little time in setting up a last-16 meeting with Northern Ireland's Mark Allen by taking the first two frames of the evening
'An absolute masterclass' - O'Sullivan makes back-to-back centuries
Video content
Video caption: Best shots: O'Sullivan makes back-to-back centuries against McGill at World Snooker ChampsBest shots: O'Sullivan makes back-to-back centuries against McGill at World Snooker Champs
Watch the best shots as reigning world champion Ronnie O'Sullivan makes consecutive centuries during his second-round match against Anthony McGill.
Last time out
Last year’s final saw Ronnie O'Sullivan claim his sixth World Championship title with a dominant 18-8 victory over Kyren Wilson at Sheffield's Crucible Theatre.
O'Sullivan drew level with Ray Reardon and boyhood hero Steve Davis on world crowns, and surpassed Stephen Hendry on the all-time list of ranking event wins with a record 37 titles.
Although Wilson battled back to 10-7, O'Sullivan wrested total control with a run of eight frames on the Sunday.
O'Sullivan, 44, was the oldest champion since Reardon, who was 45 in 1978.
It was the biggest winning margin in a final since 2008, when O'Sullivan defeated Ali Carter by the same scoreline.
Video caption: How the Rocket Ronnie O'Sullivan won world title number sixHow the Rocket Ronnie O'Sullivan won world title number six
How can I watch the World Championship?
All times are BST and subject to late changes
BBC iPlayer
Full BBC TV and online listings for day seven of the World Snooker Championship.
Friday 23 April
Live coverage
10:00-12:00 - BBC Two
13:00-18:00 - BBC Two
19:00-21:00 - BBC Four
10:00-14:00, 14:30-18:00 & 19:00-22:30 - BBC Red Button and BBC Sport website & mobile app
Highlights
23:20-00:10 - BBC Two
06:20-07:10 & 09:10-10:00 - BBC Red Button (repeat)
World Championship Extra
00:10-02:10 - BBC Two
07:10-09:10 - BBC Red Button (repeat)
What is it?
2021 World Snooker Championship
The World Championship is snooker's biggest event and has been staged since 1927. It has been hosted in its modern form by Sheffield's Crucible Theatre since 1977.
It is one part of snooker's 'Triple Crown' events alongside the UK Championship and the Masters.
The event has seen some of the biggest names in snooker throughout the decades win the trophy, including Stephen Hendry (seven titles) and Ronnie O'Sullivan (six titles).
The event returns to its usual spring dates after 2020’s edition was held in August due to the Covid-19 pandemic.
Getty ImagesCopyright: Getty Images
How to get into snooker
Get Inspired
#GetInspired
Video content
Video caption: Get Inspired: How World Snooker is helping build confidence in the communityGet Inspired: How World Snooker is helping build confidence in the community
Whether you choose to play competitively or socially, snooker is sure to get your brain working.
It requires skill and concentration and will improve your focus and hand-eye coordination.
Anyone can play regardless of age, gender or ability and it's not an expensive sport to get into.
Snooker is essentially a simple sport, once the rules of the game have been learnt - to do just that click here.
Live Reporting
All times stated are UK
BBC SportCopyright: BBC Sport 
Getty ImagesCopyright: Getty Images Video caption: Best shots: O'Sullivan makes back-to-back centuries against McGill at World Snooker ChampsBest shots: O'Sullivan makes back-to-back centuries against McGill at World Snooker Champs Video caption: How the Rocket Ronnie O'Sullivan won world title number sixHow the Rocket Ronnie O'Sullivan won world title number six 
Getty ImagesCopyright: Getty Images 
Video caption: Get Inspired: How World Snooker is helping build confidence in the communityGet Inspired: How World Snooker is helping build confidence in the community
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Read moreWhite v Knowles in World Seniors draw
Defending champion Jimmy White has been drawn again three-time World Championship semi-finalist Tony Knowles in the first round of the 2021 World Seniors.
Knowles, 65, famously defeated defending champion Steve Davis 10-1 in the opening round of the 1982 World Championships.
The Boltonian went on to make the last four at the Crucible in 1983, 1985 and 1986.
White, 58, claimed his first World Seniors title in 2019 and followed that up last season with a dramatic 5-4 victory over Ken Doherty in the final to defend his crown.
He will be looking to make it three titles in a row when the World Seniors Championship returns to the Crucible in Sheffield from 6-9 May.
There are five former world champions in this year's draw - Doherty, Stephen Hendry, John Parrott, Dennis Taylor and Joe Johnson.
BBC Sport will have full coverage of the tournament on Red Button, iPlayer and online.
Murphy & Selby through to second round
Shaun Murphy fought back from 5-3 down to secure his place in the last 16 with a 10-7 win over over Mark Davis.
Davis, 48, was making his 12th appearance at snooker's showpiece event and outplayed the out-of-sorts 2005 champion in the opening session.
But Murphy, buoyed by a century in the final frame, reduced the gap to 5-4 and was much improved on the resumption.
Breaks of 56 and 92 and helped him win four of the next five frames for an 8-6 lead and, after sharing the next two, the world seven number got over the line with stunning 131.
Three-time champion Mark Selby joined Murphy in the second round with a devastating 10-1 demolition of qualifier Kurt Maflin.
Selby, 37, needed just two frames to progress having scored two tons and six further breaks of more than 50 in a one-sided opening session against a player who reached the Crucible quarter-finals last season.
And the Leicester potter wasted little time in setting up a last-16 meeting with Northern Ireland's Mark Allen by taking the first two frames of the evening
'An absolute masterclass' - O'Sullivan makes back-to-back centuries
Video content
Watch the best shots as reigning world champion Ronnie O'Sullivan makes consecutive centuries during his second-round match against Anthony McGill.
Last time out
Last year’s final saw Ronnie O'Sullivan claim his sixth World Championship title with a dominant 18-8 victory over Kyren Wilson at Sheffield's Crucible Theatre.
O'Sullivan drew level with Ray Reardon and boyhood hero Steve Davis on world crowns, and surpassed Stephen Hendry on the all-time list of ranking event wins with a record 37 titles.
Although Wilson battled back to 10-7, O'Sullivan wrested total control with a run of eight frames on the Sunday.
O'Sullivan, 44, was the oldest champion since Reardon, who was 45 in 1978.
It was the biggest winning margin in a final since 2008, when O'Sullivan defeated Ali Carter by the same scoreline.
Read the full report here.
Video content
How can I watch the World Championship?
All times are BST and subject to late changes
BBC iPlayer
Full BBC TV and online listings for day seven of the World Snooker Championship.
Friday 23 April
Live coverage
10:00-12:00 - BBC Two
13:00-18:00 - BBC Two
19:00-21:00 - BBC Four
10:00-14:00, 14:30-18:00 & 19:00-22:30 - BBC Red Button and BBC Sport website & mobile app
Highlights
23:20-00:10 - BBC Two
06:20-07:10 & 09:10-10:00 - BBC Red Button (repeat)
World Championship Extra
00:10-02:10 - BBC Two
07:10-09:10 - BBC Red Button (repeat)
What is it?
2021 World Snooker Championship
The World Championship is snooker's biggest event and has been staged since 1927. It has been hosted in its modern form by Sheffield's Crucible Theatre since 1977.
It is one part of snooker's 'Triple Crown' events alongside the UK Championship and the Masters.
The event has seen some of the biggest names in snooker throughout the decades win the trophy, including Stephen Hendry (seven titles) and Ronnie O'Sullivan (six titles).
The event returns to its usual spring dates after 2020’s edition was held in August due to the Covid-19 pandemic.
How to get into snooker
Get Inspired
#GetInspired
Video content
Whether you choose to play competitively or socially, snooker is sure to get your brain working.
It requires skill and concentration and will improve your focus and hand-eye coordination.
Anyone can play regardless of age, gender or ability and it's not an expensive sport to get into.
Snooker is essentially a simple sport, once the rules of the game have been learnt - to do just that click here.