Sean Penn is reportedly dating Shannen Costello, the former communications director of the actor's J/P Haitian Relief Organization.
According to People magazine, the couple went public in July and have been spotted at the beach in Malibu and dining together in Miami.
The 51-year-old actor met the brunette beauty in the fall of 2009 and the two became friends.
Costello, 26, began working with J/P in 2010 and has also worked on several documentarys, doing Rights and Clearances for "It Might Get Loud" and Davis Guggenheim's "Waiting for 'Superman.'" She has also worked at ABC News' "20/20."
Costello also worked as an archival researcher and associate producer on the 2010 documentary "Cool It" and along with Brian Grazer, will co-produce Ron Howard's film, "Under the Banner of Heaven," which is currently in development.
Sean Penn will next appear in "This Must Be The Place," where he stars as a retired rock star who seeks out his father's executioner, a former Nazi war criminal who is a refugee in the United States. The film also stars Frances McDormand, Judd Hirsch and Bono's daughter Eve Hewson is slated for release in December 2011.
Penn reportedly broke up with actress Scarlett Johansson in June after being romantically linked for several months. The two had never confirmed a relationship publicly.
Johansson, 26, and Penn, 50, were first linked together in February, months after actor Ryan Reynolds filed for divorce from the actress after being married to her for two years.