Sienna Miller's Getty movie

Dec 2, 2008, 9:25 GMT

Balthazar Getty is back with Sienna Miller © Glenn Harris / PR Photos

Sienna Miller and Balthazar Getty want to star in a film together.

The 'Factory Girl' star - who was recently reunited with the married 'Brothers and Sisters' actor following a brief split - hopes working together will win over critics of their romance.

A source told Britain's The Sun newspaper: "Her advisers are warning how unpopular that would be.

"People haven't taken to them as a pair due to the way they got together. They fear people will find it a bit too sickly - as though they are rubbing his wife's face in it.

"But Sienna insists it could be movie gold and is looking for a script."

Sienna, 26, was widely criticised when she began dating 33-year-old Balthazar - who has four children with his estranged wife Rosetta - with people blasting her for romancing a married man.

Following the news of the affair, Rosetta fled the US taking their children with her.

Sienna and Balthazar separated last month, allegedly over her love of partying, but reconciled last week.

The couple were spotted walking her dogs in London's Maida Vale district last week, confirming they were an item again.

An onlooker said: "We drove past them and they looked very together. Sienna looked really pretty and so happy."