Catherine Zeta-Jones has turned down a role in a new Marilyn Monroe movie so she can be with her sick husband Michael Douglas.

The Welsh actress had been offered the part of screen siren Vivien Leigh in upcoming biopic 'My Week With Marilyn', but declined the role because she doesn't want to be away from Michael - who his currently receiving treatment for throat cancer - for more than 48 hours.

A source said: "It isn't a huge role, but filming would take a week out of her schedule and she wasn't prepared to do that. She had to say no."

Catherine would have starred alongside Michelle Williams - who is playing Marilyn - and British star Emma Watson in the movie.

Producers are now believed to be close to casting another actress as Vivien.

Earlier this week, Catherine revealed Michael was responding well to his treatment, which includes eight weeks of radiation and chemotherapy.

The 41-year-old actress - who has two children, Dylan, 10 and Carys, seven, with the 'Wall Street: Money Never Sleeps' star - said: "Everyone couldn't be happier with his progress. He's holding up with great strength and dignity."