Denise Richards, Charlie Sheen, and Brooke Mueller Credit: Jesse Grant/; Jordan Strauss/ (2)

Friendly exes is an understatement.

Denise Richards threw a party at home in Beverly Hills over the weekend for ex-husband Charlie Sheen's ex-wife Brooke Mueller.

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The 41-year-old actress tweeted about the unusual gathering on Sunday, writing, "Having a party today . . . ex-wife No. 2 (me) is having ex-wife No. 3 (Brooke) birthday party at my house . . . oh and our ex-husband will be here. How's your Sunday?"

According to E! News, the exes and all their children helped Mueller celebrate her 35th birthday Sunday along with family and friends. 

Sheen, 46, and Mueller divorced on May 2, 2011 after three years of marriage. They have two children together, twin sons Bob and Max, 3.

The Anger Management actor was married to Richards from June 2002 to November 2006. They share daughters Sam, 8, and Lola, 7. Richards also adopted a baby girl in 2011 named Eloise.

The Madea's Witness Protection actress told Rolling Stone in June 2012 that she and Sheen "are like best friends now. Confidants. He tells me everything."