Roger Federer is being invited to make his return to court at a Berlin grass-court exhibition event in mid-July, organizers have said.
There are plans for a pair of three-day events featuring six men and six women in Berlin. The first is on the grass courts of Steffi Graf Stadium, where a WTA tournament was originally supposed to be played this season, and the second on hard courts in an airplane hangar.
The men's field includes Dominic Thiem, Alexander Zverev, Nick Kyrgios and Jannik Sinner, with two more players to be announced.
"We'll of course also ask Roger Federer," said organizer Edwin Weindorfer, who also runs the Stuttgart event were Federer has often played.
The 20-time Grand Slam champion has not played competitively since undergoing knee surgery following the Australian Open. He was scheduled to return during the grass-court season and recently said he is not hitting extensively during the suspension of tour competition.
The events, which will offer €200,000 in prize money, will have two sets with a third-set match tiebreak.
Germany's Angelique Kerber has also been asked to join a field that includes Elina Svitolina, Kiki Kertens, Julia Goerges and Andrea Petkovic.
It joins at least half a dozen other events that have been planned across Europe while regular professional competition is stopped.