The pair met while Sean Penn was filming the 1990 Irish mob movie State of Grace. At the time, he was considered one of the bad boys of Hollywood. He had married and divorced Madonna and occasionally tussled with photographers.
Robin Wright Penn once said she and her husband complemented each other. She seemed to provide a calming influence over him, and he helped her gain confidence.
"He helped me to believe that I could be strong and stand up for myself," the actress told the Los Angeles Times.
Penn directed this year's Into the Wild, which is considered a front-runner for major awards.
Also splitting up are hip-hop mogul Jay-Z and Def Jam Records.
Universal Music Group said last week that Shawn "Jay-Z" Carter is stepping down as president of its Def Jam Records unit, effective by the end of the year.
Carter, 38, has been president of the rap label since 2005, and has signed acts including R&B singers Rihanna and Ne-Yo.
A top-selling rap artist, Jay-Z, however, will continue recording for Universal's Roc-A-Fella/Def Jam label. The company did not give a reason for his decision to quit the executive suite.
Carter was No. 9 on Forbes magazine's Celebrity 100, the annual list of the world's most powerful - and best paid - celebrities, with an estimated compensation of US$83 million.
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