Roger Federer will partner long-time rival Rafael Nadal in the final match of his glittering career at the Laver Cup in London on Friday.
The Swiss great has enjoyed a storied rivalry with the Spaniard over nearly two decades and together they have won 42 Grand Slam singles titles in a golden era for the men's game.
The two veterans, representing Team Europe at the Laver Cup, will face Team World doubles opponents Frances Tiafoe and Jack Sock in Friday's evening session at the O2 arena.
The six-strong Team Europe also includes Novak Djokovic and Andy Murray -- the other two members of the so-called "Big Four".
Federer, whose most recent competitive match was a loss to Hubert Hurkacz in last year's Wimbledon quarter-finals, has been struggling with a knee problem and will not play singles at the Ryder Cup-style event in London.
Italian Matteo Berrettini will take Federer's place over the weekend.
"Of course, it's super special playing with Rafa," Federer said at a packed pre-tournament press conference on Thursday. "Feels really different, you know.
"Also just walking out on court and having the chance to play with the likes of Rafa or Novak also in the past has been an amazing experience for me.
"So to be able to do that one more time, I'm sure it's going to be wonderful. I will try my very best. I hope to be good out there, and of course I will enjoy it but it will be hard."
- 'Unforgettable' -
Nadal, who first played Federer on the ATP Tour in 2004, said he was looking forward to an "unforgettable" match alongside the Swiss.
"After all the amazing things that we shared together on and off court, to be part of this historic moment is going be something amazing, unforgettable for me," said the 36-year old.
Nadal, who has won a record 22 Grand Slam singles titles in men's tennis, said he was proud of his friendly rivalry with Federer.
"Not easy sometimes, because we are playing for such an important things for our tennis career," he said.
"But at the same time we were able to understand that at the end, personal relationships are more important than sometimes professional things. We were able to handle it I think the proper way."
The Spaniard, who won the Australian Open and French Open this year, said it would be a difficult moment for him as well as Federer.
"One of the most important players, if not most important player in my tennis career, is leaving," he said.
"At the end, to live this moment will be difficult. Of course I am super excited and grateful to play with him."
Djokovic, who has 21 Grand Slam titles, said it was a "huge privilege and honour" to be on the European team.
"At the beginning of my career I was losing most of the matches between Roger and Rafa in the Grand Slams, and they have contributed a lot to the player I am today, to figuring out how I can turn the tables. So I'm very grateful to be part of that era."
Britain's Murray, who has won three Grand Slams, said the way Federer was finishing his career alongside Nadal, with Australian great Rod Laver in the stands, "feels right".
European team captain Bjorn Borg, himself the winner of 11 Grand Slam titles, praised Federer's contribution to tennis over his long career.
He said: "What (Federer) did for the sport all around the world, it's amazing...What he did for so many years, it's fantastic."
Team World, skippered by US great John McEnroe, also includes America's Taylor Fritz and Canadian Felix Auger-Aliassime.
Murray, making his debut at the Laver Cup, will take on Australia's Alex de Minaur at the start of the night session in London on Friday.
In the day session Norway's Casper Ruud faces Sock, while Greece's Stefanos Tsitsipas meets Argentina's Diego Schwartzman.