Kristen Stewart and Robert Pattinson

The couple - who rekindled their relationship at the end of last year after splitting following the actress' affair with director Rupert Sanders - splashed out on the singing machine so they enjoy their favourite pastime in the comfort of their own luxury home, complete with a stage and atmospheric lighting.

A source told The Sun newspaper: "They both absolutely love karaoke. They used to go to bars whenever they could, but more often than not they'd get hassled by people.

"So Rob surprised Kristen with their own machine. It's top-of-the-range stuff with built in disco lights, a huge screen and even its own mini stage."

Rob, 26, and 23-year-old Kristen are so proud of their new purchase they have already invited friends and neighbours around to join in the fun, holding late-night karaoke parties.

The source added: "Now they have karaoke parties at their home in the Los Feliz neighbourhood of Los Angeles with all their friends. They go on until the early hours - even after a night out they head back to Rob and Kristen's got a good old late-night sing-along."

The heartthrob actor has a favourite song he chooses when picking up the microphone and he is such a fan of the musician behind it, he knows the lyrics off by heart.

The source said: "Rob always goes Robbie Williams' song 'Angels'. Apparently he's brilliant at it. He used to sing it loads when he was growing up.

"He doesn't even look at the words on the screen - he knows them off by heart."