Rihanna could reportedly be a "shock" judge on The X Factor.

Simon Cowell recently announced that he would be returning to the UK panel of the talent show, along with singer Cheryl Cole.

Further judges are yet to be confirmed and Rihanna, 26, sparked speculation she could be the third when she jetted in to London yesterday.

“Simon and Cheryl have two months to find someone to sit in that chair and they want to get the right person," a source told British newspaper Daily Star.

“This year is an important one for The X Factor. Simon can’t be complacent and has to come back with a real A Team.

“Rihanna would be a shock selection because she is not an obvious choice for a family show – but that’s what he wants.”

The star's decision to visit England's capital may not be completely business related.

Her rumoured boyfriend Drake is performing the final dates of his Would You like a Tour? shows in London, with the first of three kicking off at the O2 Arena last night.

The Diamonds singer watched Drake, 27, take to the stage and perform hits such as Pound Cake and Crew Love.
“This is the happiest I’ve been in a long time," he gushed to the crowd.

Other stars who are rumoured to be taking a judging role on The X Factor include Ellie Goulding, Joss Stone and former Spice Girl Mel B.