Novak Djokovic, Rafael Nadal & Roger Federer part of star-studded line-up for Cincinnati Masters

Novak Djokovic, Rafael Nadal and Roger Federer -- the three men tied on 20 Grand Slam singles titles -- are all on the entry list for the Western & Southern Open in Cincinnati.

Also on the entry list are World No. 2 Daniil Medvedev, defending US Open champion Dominic Thiem, and recent Grand Slam finalists Stefanos Tsitsipas, Alexander Zverev and Matteo Berrettini.

The tournament is a combined ATP & WTA event. Also known as the Cincinnati Masters on the men's side, it is the second of two Masters 1000 events that form part of the U.S. Open Series leading up to the hardcourt Major at the end of August.

The tournament, which was moved to New York last year due to the COVID-19 pandemic, will take place from August 14 to August 22 at the Lindner Family Tennis Center in Mason, Ohio.

All of the top 37-ranked players in the world are on the entry list for the Cincinnati Masters, along with former top 5 player Kei Nishikori, who has used his protected ranking of No. 10 to enter the tournament.

ATP1000 Cincinnati entry list, source @DartsTennis pic.twitter.com/S5o8jafTxW

— Michal Samulski (@MichalSamulski) July 21, 2021

Roger Federer will be aiming for a record-extending eighth Cincinnati title

Roger Federer holds up the trophy after defeating Novak Djokovic to win the Western & Southern Open at the Linder Family Tennis Center in August, 2015 in Cincinnati, Ohio

Roger Federer, 39, holds the record for the most singles titles at the Western & Southern Open, having triumphed in Cincinnati seven times in his career. The last of Federer's seven Cincinnati titles came in 2015. Since then, the Swiss has finished runner-up in 2018 and reached the third round in 2019.

Federer is also on the entry list for the National Bank Open (Canadian Open), which begins on August 7, but it remains to be seen how the American hardcourt season shapes up for the Swiss.

Following his quarter-final exit at Wimbledon earlier this month, Federer pulled out of the Tokyo Olympics due to a setback with his knee.

The Swiss, who turns 40 next month, returned to action in March tafter more than a year away from the tour following double knee surgery. Federer, now ranked ninth in the world, is currently in Croatia as he works his way back to full fitness.