Brad Pitt has still not signed his contract for Ocean's 13, the final part in the trilogy.

The star is currently in Namibia, Africa with Tomb Raider star and girlfriend Angelina Jolie, who is expecting their first child.

Best friend George Clooney, who plays Danny Ocean and is one of the producers on the new film, is said to be very worried about the situation.

A source told The Sun: "Brad has not been able to confirm 100 per cent that he will be available - and that's making George very anxious.

"Instead of being there to work on the project, Brad is in the middle of Africa. People are worried that he will prefer to carry on being a dad rather than go back to work."

The baby is due some time early next week.