Tributes have been paid to William Dunlop after he was killed in an incident at the Skerries 100 road races in County Dublin on Saturday.
Dunlop, 32, was taking part in practice for the event when the crash happened.
The Ballymoney man was a member of the renowned Dunlop family and was a winner at the North West 200 and Ulster GP.
William's father Robert died as a result of an accident at the North West 200 in 2008, while his uncle Joey was killed in a crash in Estonia in 2000.
A statement released by the Loughshinny Club, the organisers of the Skerries 100, said that they "deeply regretted that William Dunlop has passed away following injuries received in a tragic accident that occurred during practice which took place today, 7 July 2018".
It is understood that William was taking part in an Open race practice session on his Temple Golf Club-backed R1 Yamaha when he crashed at the Sam's Tunnel section of the 2.9-mile circuit on the third lap at about 17:00 BST.
Red flags were immediately displayed to halt the session and medics and Gardaí (Irish police) attended the scene.
Family, friend and politicians have been paying tribute to the County Antrim man.
BBC Northern Ireland Sports presenter Stephen Watson described him as "one of the nicest, most genuine people you could ever meet".
The DUP leader Arlene Foster said she was "shocked and saddened" by the passing of a "talented sporting legend".
Former Northern Ireland footballer Keith Gillespie said it was devastating news and "a nicer guy you couldn't wish to meet".
Eleven-times North West 200 winner Phillip McCallen tweeted that Dunlop was "one of the most genuine people you could ever meet".
"I'm absolutely gutted. We all feel the hurt for the family. It's another sad day for road racing," said Dungannon-based road race champion Ryan Farquhar.
North West 200 Race Director Mervyn Whyte said his heart broke when he heard the news.
Shocked and saddened by the passing of NI’s talented sporting legend, William Dunlop. Motorcycling was his life and he will be forever remembered for his many achievements, both in Ballymoney and across the world.— Arlene Foster (@DUPleader) July 7, 2018
"He was an absolute gentlemen" he said.
Radio Ulster motorcycle racing analyst Liam Beckett knows the family well and described him as "one of the nicest, most humble, unassuming young lads you could ever wish to meet in life".
So sad to hear about William Dunlop. Thoughts go out to his family at this difficult time. Gone too soon— Tommy Bowe (@TommyBowe14) July 7, 2018
The late Joey Dunlop's wife Linda said words could not describe how the family was feeling.
"My whole love goes out to Janine Brolly (William Dunlop's partner) and wee Ella and all the family - and I know that my son Gary Dunlop will be breaking his heart right now," she said.
"I have to say William just reminds me so much of Joey in is mannerism and a lovely kind family man," she added.
Everyone associated with the Vauxhall International North West 200 is absolutely devastated to learn of the death of William Dunlop in an incident today at the Skerries 100. Our sincere sympathies are with his partner Jeanine, his daughter, brothers, mother and extended family. pic.twitter.com/82Qyip3X5g— North West 200 (@northwest200) July 7, 2018
He achieved four wins at the North West 200, including successes in the 125cc and 250cc races in 2009, a Supersport triumph in 2012 and a Superbike victory in 2014.
William won seven races at the Ulster Grand Prix in Dundrod, three in the Supersport class, two on 125cc machines and two in the 250cc class.
This is truly shocking news once more for The Dunlop family circle , Northern Ireland and the Road racing fraternity.— Eamonn Holmes OBE (@EamonnHolmes) July 7, 2018
Sincere condolences to William's partner and daughter.
So so sad . #WilliamDunlop #Rip https://t.co/yhGbcBcfTu
His best result at the TT was a second place in TT Zero in 2016, while he also finished third on four separate occasions.