Sienna Miller is moving to America for the summer.

The 28-year-old actress - who reconciled her romance with actor Jude Law at the end of last year while they were both staring in theatre productions on New York's Broadway - has reportedly agreed to travel back to the US to stay with the 'Alfie' star while he works on his new movie 'Contagion'.

A source told the Mail on Sunday newspaper: "Sienna is determined to make it work with Jude this time.

"She doesn't want to let him out of her sight. She loves him and wants them to stay together, so she is prepared to move wherever he is."

It was recently claimed that 37-year-old Jude - who saw his engagement to Sienna end in 2005 when he slept with his children's nanny - has asked the actress to move into his London home.

While the Factory Girl' star agreed, cautious Sienna has insisted on keeping her own house in case things go wrong again.

A source said: "Jude has promised there will be no affairs and Sienna demands total honesty.

"If either one is unhappy she has told him they must end it."

Jude and Sienna spent the festive period on the Caribbean island of Barbados together with his three children, Rafferty, Iris and Rudy, from his marriage to Sadie Frost.

Last year, Jude became a father for the fourth time after American model Samantha Burke fell pregnant following a brief relationship.