Federer's boy band belts out a classic

Tennis legend Roger Federer has made a glorious return to music with his new and improved boy band The Backhand Boys.

Featuring German legend Tommy Haas, Bulgarian Grigor Dimitrov and Serbian Novak Djokovic, the boys belted out a rendition of Hard to Say I'm Sorry by Chicago.

It's the second time Federer's boy band has released a song, after a far less impressive effort during the Australian Open in January.

While their most recent song is far improved, it's hard to imagine that's all down to a singing practice.

Auto-tune certainly played a large part.

"No seriously, we're actually starting a boy band: The one handed #BackhandBoys," Federer said on his Facebook video.

The boys belt out a note. Pic: Facebook

The Swiss maestro had plenty of reason to be singing after Aussie firebrand Nick Kyrgios pulled out of the pair's quarterfinal clash at Indian Wells with sickness.

The Australian, ranked 16th in the world, had beaten second seed Novak Djokovic in the round of 16 to set up a quarter-final against Federer but was unable to take to the court after a troubled night.

"Unfortunately I am unable to play today due to sickness," he wrote in a statement posted to his Twitter feed.

"At this stage we think it's food poisoning, and I'm praying it's nothing more."