The actress has been filming in the Czech Republic alongside co-stars Christopher Eccleston and Dennis Quaid and has had to endure boxing lessons and weight-lifting sessions.

But supportive boyfriend Rhys Ifans has been phoning her constantly from the set of his own film, The Boat That Rocked, in Dorset.

“Rhys is worried how tired she is,” says a friend. “She is really giving her all to this film which is tipped to be one of the biggest of 2009.

“But Rhys’s voice helps her while she’s struggling with the demands. He spends nights on the phone to her trying to soothe her to sleep.

“His voice relaxes her and he tries to take her through a meditation routine so she can empty her mind.”

A cup of cocoa might help, too.