Kristen Stewart has reportedly bought Robert Pattinson a ￡50,000 piano.

The 21-year-old actress - who plays Robert's onscreen wife in the 'Twilight Saga' - has apparently treated her man to the instrument to mark their third anniversary.

A source said: "Kristen wanted to get a huge surprise for Rob for their anniversary later this month.

"Robert's been playing the piano his whole life and admits it's the perfect escape for him when the showbiz world, paparazzi and fans get too much. Playing the piano is Rob's therapy when he needs to be alone, to think, to get emotional and creative.

"He's really musical and loves to sing as well.

"Kristen has been searching around specialised, high-end piano shops in Los Angeles. She's been talking to top musicians about the best piano for months. Robert has always wanted a Steinway grand, so that's what she opted for.

"She blew ￡50,000, knowing that he'd love it."

The 'Snow White and the Huntsman' star is believed to have already splashed out on three vintage guitars for her music-mad 25-year-old boyfriend.

Talking to the Daily Star newspaper, the insider added: "He played classical guitar from the age of five, for about eight years."