WATCH: Roger Federer warms up with Rafael Nadal ahead of final match

WATCH: Roger Federer's Laver Cup press conference

When Roger Federer speaks, fans listen. And when Roger Federer announces the final practice session of his career, fans turn up in droves.

That’s what happened on Friday afternoon at The O2, when the 20-time Grand Slam winner dropped a note to fans on social media announcing that he was currently on his way to the venue with doubles partner Rafael Nadal:

Team Europe’s Federer and Nadal were fine-tuning their game ahead of the final match of the Swiss’ career, a doubles clash against Frances Tiafoe and Jack Sock.

The practice session drew crowds of fans, who lined up outside the public courts to get a glimpse of the action.

“At the end, living this moment will be difficult. Of course I am super excited and grateful to play with him," Nadal said of playing doubles with Federer. "I just think I gonna try to do my best in every single way, to help to have this moment even more special than what it's gonna be.”

“Of course, it's super special playing with Rafa. Feels really different, you know," Federer said of playing doubles with Nadal. “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.”