Roger Federer has been drawn in the same group as Alexander Zverev for next week's ATP Finals in London.
With Rafael Nadal and Federer seeded one and two, they were guaranteed to be kept apart for the group stages of the tournament at the O2 Arena.
Federer looks to have marginally the tougher group, with third seed Zverev, fifth seed Marin Cilic and eighth seed Jack Sock his opponents.
Federer tweeted that he will play American Sock, who catapulted himself into 2017's top eight by winning the Paris Masters last weekend, in the opening singles match on Sunday afternoon.
Sock and 20-year-old Zverev will both make their debuts along with Grigor Dimitrov, who joins Nadal, fourth seed Dominic Thiem and seventh seed David Goffin in the Pete Sampras group.
Fourth doubles seeds Jamie Murray and Bruno Soares will take on top seeds Lukasz Kubot and Marcelo Melo, Bob and Mike Bryan and Ivan Dodig and Marcel Granollers.