Novak Djokovic and Roger Federer have been drawn in the same group at the ATP Finals tournament, which starts on Sunday at London's O2 Arena.
Five-time winner Djokovic and six-time winner Federer are drawn alongside Dominic Thiem and Matteo Berrettini.
World number one Rafael Nadal is in a group with Daniil Medvedev, Stefanos Tsitsipas and Alexander Zverev.
Earlier on Tuesday Nadal said he plans to compete in London, despite pulling out of last week's Paris Masters.
More to follow
How to follow ATP Finals on the BBC
Live coverage of one match per day will be shown on BBC TV and the BBC Sport website and app, starting with the opening match at 13:50 GMT on Sunday on BBC Two.