Looks like George Clooney's bachelor status is here to stay. The Argo producer's year-and-a-half-long romance with girlfriend Stacy Keibler has run its course, multiple sources reveal in the March 18 issue of Us Weekly, on stands now.

Insiders say the pair have been increasingly butting heads in recent months. "They have little in common," one source explains of the former wrestler, 33, and her 51-year-old beau. "She likes to go out and have fun. She's been feeling the age difference."

Clooney's friends are a factor, too. According to one insider, the Oscar winner's buddies aren't wild about Keibler's pals. Adds another source: "The end is near. It's a matter of time."

For more on the couple's doomed relationship -- and exclusive details on what Keibler really thinks of Clooney's famous Lake Como villa -- watch this week's Hot Stuff video, as explained by Us Weekly entertainment director Ian Drew and special guest Andrea Canning, correspondent for Dateline NBC.

Other stories in the roundup: how Jason Segel changed Michelle Williams; Bethenny Frankel blows off steam amid divorce drama with Jason Hoppy; Jake Gyllenhaal has a new girlfriend; and much more!