Tom Cruise and Katie Holmes Photo: AFP

Katie Holmes could earn up to $33 million for being Tom Cruise's wife. The massive sum has been revealed in the pre-nuptial agreement signed by the former Dawson's Creek actress and the Hollywood actor.

According to the legal document, Katie is entitled to a set figure of $3 million a year and up to $33 million for the total period of time she spends as Mrs Cruise.

However, if their nuptials last longer than 11 years, California's community property law will entitle the brunette star - who gave birth to Tom's baby daughter, Suri, two months ago - to half of Tom's entire fortune.

The new parents are set to tie the knot later this year, and rumours have circulated that Katie is desperate to marry the actor so she would be able to afford to fight him for custody if they ever split.

A source told Newsweek magazine: "If she walks now, Tom will fight her for custody of Suri and Katie can't outlast him in court. She knows she needs to marry him to get the money to fight him for custody, if it comes to that."