World number one Roger Federer plans to let his hair down when he takes on closest rival Rafael Nadal in the "battle of the surfaces" next month.
Federer has won 10 Grand Slams
Federer and Nadal will go head-to-head in Mallorca on 2 May on a court that is clay at one end and grass at the other.
"It might seem crazy, especially at this time of the season, but we enjoy playing tennis for fun," Federer said.
"It does not always have to be serious. The result is not the most important thing. It's more about having fun."
Federer is the undisputed king on grass, having won Wimbledon for the last four years, while double French Open champion Nadal has won 63 straight matches on clay.
"It's exciting. The idea was there six or nine months ago," added Federer, who has won 10 Grand Slams.
"I said it would be fun to do something like this. It has never happened before."