During a day of incessant rain in England on Sunday, Murray, who was playing at Queen's, asked his Twitter followers what the players could do to entertain the fans, suggesting "Karaoke would be great!!?"

Serena, who was being kept off the practice court at Eastbourne, revealed she had a portable karaoke machine with her and tried to commandeer Murray to join her in a singing session.

"Omg I LOVE karaoke!!! Let's do it on rain delays! What's your go to song?? I'm in!!!!!! Let's go!:)" she tweeted.

And after winning her opening match at Eastbourne on Tuesday, Williams was still keen, promising: "We'll do it at Wimbledon. I'll bring it and I'll force him to sing."

Murray said his song of choice would be REM's "Losing My Religion." Williams went for "Straight Outta Compton" by NWA.