Marat Safin will work with Roger Federer's former coach Peter Lundgren for the clay and grasscourt seasons.
Lundgren coached Federer to the Wimbledon title last year
Wimbledon champion Federer split with Lundgren at the end of last year just weeks after winning the end-of-season Masters Cup.
"We'll see if it works - you have to feel comfortable with him as a person," said Safin, who was beaten by Federer in January's Australian Open final.
"He is a partner off the court and you have to spend a lot of time with him."