British talent Tom Pidcock and ex-Team Sky rider Richie Porte will ride for Ineos Grenadiers next season.
Pidcock won this year's Under-23 Giro d'Italia, came third in the 2019 under-23 road race World Championships and is an ex-world junior time trial champion.
The 21-year-old took silver at the 2020 World Cyclocross Championships and is the reigning British champion.
Australian Porte, third at this year's Tour de France, spent four seasons with Team Sky from 2012 to 2015.
Laurens de Plus and Dani Martinez have also been recruited to join fellow new arrival Adam Yates, who was announced for 2021 last month.
Belgian climber De Plus made his Tour de France debut last season and claimed overall victory at the BinckBank Tour, while Martinez has a Tour de France stage win and overall victory at the prestigious Criterium du Dauphine to his name.
Pidcock, who will represent Great Britain in the elite men's road race at the World Championships in Italy this weekend, said he was excited and proud to sign.
"Like so many British cyclists of my generation, I have always aspired to race on the road with this team - to me, the best in the world," said Pidcock, who is also a former junior and under-23 cyclocross world champion.
"I just want to keep racing, learning and growing as a bike rider, and having the opportunity to do that in this team is amazing."
Team boss Sir Dave Brailsford said: "It's clear Tom is one of the most exciting young riders in world cycling and part of a new era of incredible all-round talents.
"Richie's richly deserved podium at the Tour de France once again demonstrated that he's one of the best riders in the peloton.
"We already know how each other works, he knows how we race, and with the wealth of experience that Richie now has he has so much to offer the team. We really are extremely pleased to welcome him back."
BBC Sport's Matt Warwick
These are uncertain times for Ineos Grenadiers. Following Egan Bernal's dramatic loss of form during the Tour de France, it's hard to know who their out-and-out strongest talent is right now.
But in Pidcock there is one for the future. It feels like his chance on the World Tour is overdue - he has the talent to be there; it remains to be seen whether he can thrive.
It's exciting for the team, whose billionaire owner Sir Jim Ratcliffe is keen on preserving Ineos' British identity within the sport - reflected in the fact they have already signed Adam Yates for 2021.
As one of the peloton's most well-liked riders, Porte's third place at the Tour was well received. And, at 35, he will be a safe pair of hands to help usher in a new era.