AceShowbiz -

The movie siren is in love again. Sienna Miller has fallen for her yet another co-star. Following her break up with on-off boyfriend Jude Law and her brief romance with Jamie Burke, the beauty is now reported to be dating actor Matthew Rhys.

Miller and Rhys are co-stars in the drama romance "The Edge of Love," slated to hit theaters by next year. They met upon being introduced by mutual pal actress Keira Knightley who encouraged their romance after the three went out for a dinner back in May.

"This is the first bloke Sienna has been serious with since she finally split with Jude," a source in the know was quoted as telling The Sun. "These allegations of her being with Diddy and splitting up his relationship with Kim Porter are awful. But they have actually worked in her and Matthew's favor a bit. It has taken the heat off their relationship because people have been looking for a spark between her and Diddy."

As of Burke, the source tend to claim the model "was just a distraction for Sienna. She was on the rebound and wanted some fun - and that's what she and Jamie had. But now she wants more." On Sienna and Matthew's romance, the source revealed, the actor "is really into her but they have both been trying to keep it very quiet, only telling close friends."

Miller and Burke split hot on the heels of reports she's making out P. Diddy. Both stars denied any romance occurred between them though.