AceShowbiz -

Sean Penn is reportedly trying to rekindle romance with his ex Charlize Theron. A source tells Radar Online that the "Milk" actor drunk dialed the "The Huntsman" actress after he attended U2's special show at Roxy Nightclub in Los Angeles on May 28.

The source says, "During the after-party, Sean was very much acting like a single man on the prowl. Sean had been partying with the band, and he decided to call Charlize very late - it was obvious he was feeling no pain. He wanted to go over to Charlize's house, but she said no way...she refused to be a booty call!"

According to the site, Sean and Charlize split after "The Last Face" filming took a toll on their relationship. "Working together on the project definitely took a toll on the relationship," an insider told the site, "Everyone knows how intense Sean is, and there is no exception on movie sets. Charlize felt he was overly critical of her at times. Separating work and personal became hard, and the lines were definitely blurred."

The insider added, "Sean is also a notorious flirt, and Charlize didn't like it. Things just moved very fast after they became engaged. But Sean moved out of Charlize's house three weeks ago."

It was previously reported that Charlize was the one who initiated the split.