Michael Jackson will sing with his eldest son on the opening night of his London residency.

The 50-year-old singer is planning to invite 12-year-old Prince Michael I onstage to perform a surprise musical number during the first of his 50 'This Is It' shows at London's O2 arena in July.

A source said: "What better way to introduce his son to the music world than to have him come onstage during the most anticipated concert in history? Of course nothing's set yet, and Michael is always changing his mind."

But friends claim Jackson has an ulterior motive for the father-son performance - he is hoping it will distract people from talking about the likelihood of him completing all the shows.

The source said: "He knows what people are saying about him not being able to do all 50 shows. Don't expect him to address it publicly."

The 'Thriller' singer is also planning to ask Leona Lewis to join him on stage.

He reportedly wants her to sing his sister Janet Jackson's part in their 1995 hit 'Scream'.

Another source said: "Michael has a list of singers he feels could do Janet justice — and Leona is top. He hasn't approached her yet but he's a big fan of everything she has achieved.

"She's massive all around the world and he feels this duet would give both their careers an even bigger boost."