KEY POINTS:
Sienna Miller and Balthazar Getty are reportedly back together.
The Edge of Love actress - who said at an event earlier this month she was "single at the moment" - was spotted walking her dogs and laughing with the Brothers and Sisters star in London's Maida Vale district.
An onlooker said: "We drove past them and they looked very together. Sienna looked really pretty and so happy."
Sienna's love of partying is believed to have been to blame for her split from 33-year-old Balthazar, who is married with four children.
A source said: "Sienna is only 26 and loves to go out. At first Balthazar was excited by her beauty but eventually realised he should be back with his wife, and that Sienna represented a phase from another point in his life."
Sienna was widely criticised when she began dating Balthazar, with people blasting her for dating a married man.
Following the news of the affair, Rosetta fled the US taking their four children with her.
- BANG! SHOWBIZ