Oscar-winning star Reese Witherspoon and her husband, actor Ryan Phillippe, are separating after more than seven years of marriage.
The couple recently attended a screening of Flags of Our Fathers
The couple, who have two children, married in 1999 after working together on the film Cruel Intentions.
"They remain committed to their family," their publicists said in a joint statement.
Witherspoon, 30, won the best actress Oscar earlier this year for her role in the Johnny Cash biopic Walk the Line.
Phillippe, 32, played a young police officer in the film Crash, which went on to win the Academy Award for best film.
"We are saddened to announce that Reese and Ryan have decided to formally separate," publicist Nanci Ryder said in the statement.
"We ask that you please respect their privacy and the safety of their children at this time."
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.
Witherspoon won critical acclaim for her role in Walk The Line
She played country singer June Carter in Walk The Line, alongside Joaquin Phoenix.
Phillippe is currently starring in Clint Eastwood's latest film Flags of Our Fathers as Navy Corpsman John "Doc" Bradley, one of the US servicemen who raised the Stars and Stripes on Iwo Jima's Mount Suribachi during World War II.
The couple attended a screening of the film on 16 October.
Witherspoon is the latest best actress Academy Award winner to suffer marital problems.
In January, two-time Oscar winner Hilary Swank split from husband Chad Lowe.
In the past 10 years, six best actress Academy Award winners eventually split from the partners they thanked on Oscars night.