Novak Djokovic tweets that he is in for Tokyo Olympics

Is Novak Djokovic the best player of his generation? (2:25)

Patrick McEnroe and Darren Cahill discuss where Novak Djokovic ranks among his peers after winning Wimbledon. (2:25)

Novak Djokovic is going to the Tokyo Olympics, keeping alive his chance for a "Golden Slam."

Djokovic, 34, posted Thursday on Twitter that he had booked his flight and was proud to represent Serbia at the Olympics.

The announcement was accompanied by a video in which he wished Kojiro Owaki, who turned 6, a happy birthday. Djokovic had texted advice on using the backhand to Owaki through his father, Kosuke, in the past after watching videos of he and his older brother Yunosuke playing tennis on an Instagram account created by the father.

After Djokovic won Wimbledon on Sunday for his record-tying 20th career Grand Slam title, he said he didn't know whether he was going to play in Tokyo.

If the top-ranked Djokovic wins gold in men's singles and at the US Open, he would become the first male tennis player to complete a "Golden Slam" -- all four Grand Slam tournaments and the Olympics in the same calendar year.

Steffi Graf is the only woman to have done it, in 1988.

While Djokovic is headed for Tokyo, Roger Federer, Rafael Nadal, Dominic Thiem and Nick Kyrgios are among the top men's players who won't be competing in the Olympics.

The Associated Press contributed to this report.