The 42-year-old actor and Mueller, a real estate investor, have been engaged since last summer.
"She's just easy, and loving, and smart, and if everybody was just as happy to see me when I walk through a door as her, my life would be perfect," he said soon after the couple got engaged.
Sheen married Denise Richards in 2002. They divorced in 2006 and have been embroiled in a bitter custody battle over their two young daughters. Richards stars in the new reality show "Denise Richards: It's Complicated" on E!
Sheen briefly married model Donna Peele in 1995, and announced plans to divorce her about six months into their union.
Sheen has appeared in several movies, and currently stars in CBS' "Two and a Half Men."