Ben and Tom Youngs will become the first brothers to start a British & Irish Lions Test for nearly a quarter of a century.
Leicester Tigers director of rugby Richard Cockerill has praised the "special" achievement of his players.
Lions head coach Warren Gatland has named the pair in the starting XV for the second Test against Australia, in Melbourne, tomorrow.
The Lions will be looking to secure the series with victory in the Etihad Stadium.
Ben Youngs comes in at scrum-half in place of Wales No.9 Mike Phillips as one of five changes made to the side that defeated the Wallabies 23-21 in the first Test last weekend. Tom, pictured right, keeps his place at hooker.
The Youngs duo become the first brothers to play together in a Lions Test since the Scottish pair Gavin and Scott Hastings, in 1989.
Cockerill said he is proud of all five of his players in the 23-man squad, but said the two brothers have bestowed a great honour on the club.
"It's a great achievement for these two lads who have come through our system at Tigers," he said.
"Ben's rise through the game has been fantastic. He has gone on to play for England, now the Lions, and Tom's story just keeps going and going.
"He has played really well. To go on tour and to get in front of the other guys that have gone, especially (Richard) Hibbard who, when they went out there, was probably favourite to start. So credit to Tom yet again.
"I'm delighted for them all but for brothers to play in a Lions Test together is something very special.
"I'm very proud of them both and it's an honour they've now bestowed on the club, and that will be in the history books forever."
They will be joined in the starting Lions pack by fellow Tigers star Geoff Parling, who plays in the second-row in place of the injured Paul O'Connell.
"Geoff has done exceptionally well," said Cockerill.
"In the four-and-a-bit years from being at Newcastle to playing for England, to being a British Lion, that story in itself is as amazing as Tom Youngs' in some ways."
But there is disappointment for Tom Croft, who loses his starting spot from the first Test, being replaced by the Welsh flanker Dan Lydiate.
Croft takes his place on the bench alongside Tigers prop Dan Cole.
There is also no place in either in the starting line-up or on the bench for Manu Tuilagi, despite his impressive performance in the 35-0 victory against Melbourne Rebels on Tuesday after returning from a neck injury.
"I'm a little disappointed for Tom Croft that he is not starting because I think he's had a pretty strong tour," said Cockerill.
"Same for Manu because we know how good he can be.
"An injury on a relatively short tour when you have to make decisions for big games quite early on has been hard.
"Not to make the bench is difficult for him as well but that's life. But there is plenty of time yet and another Test match to come.
"All our lads have featured heavily and to have five in the 23 for both the first two Tests is testament to the players and the club."
The final two changes see Tommy Bowe take over from Alex Cuthbert on the right- wing, while Makovina Vunipola replaces Alex Corbisiero.
