British number one Andy Murray has been drawn to play Stanislas Wawrinka, Rafael Nadal and David Ferrer in the Ilie Nastase group at the ATP World Tour Finals in London.
World number one Novak Djokovic and seven-time Wimbledon champion Roger Federer, meanwhile, are in the Stan Smith group alongside Tomas Berdych and Kei Nishikori.
In the doubles, Jamie Murray and John Peers have been drawn in the same group as 16-time Grand Slam champions Mike and Bob Bryan.
The finals take place between November 15 and November 22 at the O2 Arena.
Stan Smith group draw:
Novak Djokovic
Roger Federer
Tomas Berdych
Kei Nishikori
Ille Nastase group draw:
Andy Murray
Stan Wawrinka
Rafael Nadal
David Ferrer
Ashe/Smith group draw:
Bob Bryan & Mike Bryan
Jamie Murray & John Peers
Simone Bolelli & Fabio Fognini
Rohan Bopanna & Florin Mergea
McEnroe/Fleming group draw:
Jean Julien-Rojer & Horia Tecau
Ivan Dodig & Marcelo Melo
Nicolas Mahut & Pierre-Hugues Herbert
Marcin Matkowski & Nenad Zimonjic