The Wales flanker's place in the team had been called into question following injury, but he has been named in the starting XV by coach Warren Gatland.
Warburton has said that captaining the Lions will be "the biggest moment" of his career.
"I have been thinking about Saturday since I was 14 years old," Clubcall.com quotes him as saying.
"It will be the biggest moment of my career, without a doubt. I thought leading Wales out against France in the World Cup semi-final and in the Grand Slam match of 2012 were special, but this will top them all.
"I suppose people will be wondering what my message will be, come the last minutes of the changing room. My honest answer is that I do not know."
The Lions are aiming to win a Test series for the first time since 1997.