The former couple, previously embroiled in a bitter custody battle over their two two-year-old twins, released Tuesday a picture of the group posing together during a weekend get-together at Sheen's Hollywood mansion.
"Harmony is our goal," Sheen told TMZ. "Sunday was a wonderful start."
In the picture, a smiling Sheen, 45, and Mueller, 33, are sitting with sons Bob and Max on their laps, as the boys eat candy.
The former "Two and a Half Men" star and his third wife have had a notoriously tumultuous relationship since they filed for divorce in 2009.
Los Angeles police accompanied Mueller to Sheen's home in early March and removed the boys from his care after Mueller claimed that the actor was physically and verbally abusive to her.
Mueller, who checked into rehab in April for substance abuse, was then targeted by her ex in one of his shows for his "My Violent Torpedo of Truth/Defeat Is Not an Option" tour. Sheen, who launched the tour after he was fired from "Two and a Half Men" earlier this year, said, "Speaking of crack addicts, have you heard about this ex-wife of mine? How do we feel about that loser?"
However, the star has now said that he wants Mueller to move to a home in his neighborhood as soon as her treatment program ends so that they can spend more time together as a family.