England internationals George Ford and Ellis Genge have both signed new contracts with Leicester.
The Gallagher Premiership club also announced fresh deals for backs George Worth and Sam Aspland-Robinson.
Fly-half Ford, who has won 65 caps, made his Leicester debut as a 16-year-old before returning to the Tigers in 2017 following a four-year stint with Bath.
Prop Genge, meanwhile, moved to the Tigers from Bristol and has become a key member of their pack.
Leicester are currently 11th in the Premiership with just one win from their first seven league games, so the contract news has come as a welcome boost.
"I want to be successful, part of a team that is winning trophies and in an environment that is doing that," England World Cup number 10 Ford told the Tigers' official website.
"If I didn't believe we could make improvements, it might have been a different story, but I genuinely believe that.
"I believe in sticking it out through tough times and coming out at the other end.
"You want to make the best decision for you, your family and the club as well."
And Leicester heed coach Geordan Murphy added: "We are in ongoing negotiations with current players, always, and continuing to work towards building and strengthening our squad for the future.
"Today's announcements are a huge boost to our group because of not only the quality of these four players, but also the people they are and the value they add as young men to our club."