Reese Witherspoon, winner of the Oscar for best actress, and her husband, actor Ryan Phillippe pose together following the 78th annual Academy Awards in Hollywood, California in this March 5, 2006 file photo.

Oscar winner Reese Witherspoon and "Flags of Our Fathers" star Ryan Phillippe are separating after more than seven years of marriage, their representatives said on Monday.

"We are saddened to announce that Reese and Ryan have decided to formally separate," their publicists said in a joint statement. "They remain committed to their family and we ask that you please respect their privacy and the safety of their children at this time."

Witherspoon, 30, and Phillippe, 32, reportedly met at her 21st birthday party before working together on the 1999 film "Cruel Intentions." They married in June of that year and have two children, 7-year-old daughter Ava and 3-year-old son Deacon.

The publicists gave no additional details about the split but the celebrity Web site TMZ.com, which broke the story, reported that Witherspoon has contacted the divorce lawyer who represented Jennifer Aniston and Lisa Marie Presley.

TMZ quoted one unidentified source as saying the breakup was not triggered by any single event but rather by "cumulative" circumstances.

Witherspoon established herself as a major box-office draw as star of the 2001 comedy "Legally Blonde" and scored a follow-up hit with "Sweet Home Alabama."

She went on to win a best-actress Oscar earlier this year for her role as Johnny Cash's country-singing sweetheart June Carter in "Walk the Line."

Phillippe is currently starring in Clint Eastwood's latest film "Flags of Our Fathers" as Navy Corpsman John "Doc" Bradley, one of the U.S. servicemen who raised the Stars and Stripes on Iwo Jima's Mount Suribachi during World War Two.