"Pamela filed for divorce last week," Anderson's rep, Tracy Nguyen tells PEOPLE. "It wasn't a happy Thanksgiving." A rep for Rock had no comment.
On Monday, Anderson posted the following message on her Web site:
Yes, it's true.
In fact, Anderson, 39, and Rock, 35, both filed divorce petitions Monday, each citing irreconcilable differences, but they gave different dates of separation. Anderson's papers said they separated before Thanksgiving weekend, on Tuesday, Nov. 21, 2006, while Rock – who filed under his real name, Robert Ritchie – said they separated on Sunday, Nov. 26. No reasons were given for the discrepancy.
Both ask that the court not get involved in awarding spousal support.
The couple held their first wedding ceremony on July 29 on a yacht in St. Tropez. In a note posted on her Web site the following day, Anderson described the nuptials as "The best most romantic wedding of all time."
They later made it legal on Aug. 3 at a Beverly Hills courthouse, and held a third, surprise wedding on Aug. 17 onstage at Nashville's Tootsie's Orchid Lounge.
Earlier this month, Anderson's rep confirmed that the actress had suffered a miscarriage while in Vancouver filming the movie Blonde and Blonder.
The marriage was Anderson's second; she was married to Mötley Crüe drummer Tommy Lee from 1995 to 1998 and has two sons with him – Brandon, 10, and Dylan, 8. Rock has a 13-year-old son, Bob Jr., with former flame Kelley South Russell.
Anderson and Rock had dated and broken up before: They first got together in spring 2001, became engaged in April 2002 and then split in June 2003.
Anderson revealed on July 18 that she and Rock were planning to wed, writing on her Web site: "I've raised my kids alone in hope of a miracle. Well my miracle came and went. And came back and came back because he knew that I'd wake up one day and realize that I was waiting for nothing. I'm moving on ... I feel like I'm finally free ... I'm in love. I'm happy."