The 41-year-old Federer will play competitively for the last time at this week's Laver Cup, turning out for Team Europe alongside Nadal, Andy Murray and Novak Djokovic - the three biggest rivals of his glittering 24-year career.
Federer, who has won 20 Grand Slam titles, has struggled with knee injuries in recent years and said last week that he would end his career after the Laver Cup in London.
The order of play released by the organisers for the opening day of the tournament showed Federer and Nadal will play the last match of the evening at London's O2 Arena against the American pair of Jack Sock and Frances Tiafoe.
"It's going to be a different kind of pressure to be part of this historic moment," Nadal, who has shared an epic career-long rivalry with Federer, told reporters.
"It's going to be something amazing and unforgettable for me. I'm super excited. maybe we can create a good moment and maybe win the match."
Federer cut a relaxed figure as he sat with his European team mates including 21-time Grand Slam champion Novak Djokovic and three-time major winner Andy Murray.
But he said the emotions could hit him on Friday.
"I'm not sure if I can handle (all the emotions) but I will try," Federer, whose presence had fans flocking to watch practice sessions on Thursday, told reporters.
"This one feels a whole lot different. It's super special playing with Rafa. "Feels very different you know."
"To be able to do it one more time, I'm sure it will be wonderful and I'll try my very best."
Nadal was asked to highlight some of his best moments against Federer, not surprisingly picking the 2008 Wimbledon final as one of his most cherished.
He also spoke warmly of their enduring friendship.
"I think we are very proud it's been a friendly rivalry," said Nadal, who beat Federer in six Grand Slam finals.
"Not easy because we are playing for such important things for our tennis careers, but at the same time we were able to understand that personal relationships are more important than sometimes professional things.
"Tomorrow is going to be special thing."
Rest of the World captain John McEnroe said there had been some "coin flicking" to see who would face Nadal and Federer in Friday's doubles - saying that whatever the result of the match it would be a magical night for tennis.
"It's a very unique situation that we are all fortunate enough to be around," McEnroe said. "This is like an incredible moment for our sport.
Sock said he was stoked to be part of an iconic night while Tiafoe, who reached the US Open semi-finals, added: "I'm just excited to play two up-and-comers!
"Both guys are absolute legends, and obviously it's Roger's last dance."
Sock opens play in Friday's first singles against US Open runner-up Casper Ruud while Murray is the evening warm up act against Alex de Minaur.
