(Photo: Reuters/Lucy Nicholson)George Clooney and his girlfriend Stacy Keibler pose with his award for best actor in a motion picture - drama for "The Descendants," backstage at the 69th annual Golden Globe Awards in Beverly Hills,

George Clooney and Stacy Keibler have reportedly split following reports claiming the couple's relationship was crumbling.

The 51-year-old Hollywood actor first began dating the former WWE pro-wrestler in 2011 and while they appeared to be happy during a recent Oscars appearance, they have since parted ways. Keibler's desire to get married and start a family has been cited as the reason for their split.

"They knew it was never going to end in marriage or babies and Stacy does want kids and a husband in the next few years," a source told The Sun UK.

On March 8, it was claimed that the pair was growing apart and subsequently headed for a split. Keibler, 33, was reportedly struggling with the 18-year age gap.

"They have little in common. She likes to go out and have fun. She's been feeling the age difference," a source told Us magazine. "The end is near. It's a matter of time."

The pair, whose relationship continues to draw interest from fans, denied reports of a split in September while celebrating their 1-year anniversary in Italy.

"A story published by a London tabloid, The Sun, concerning George Clooney and Stacy Keibler is not true," the representative stated. He added that the article is a "total fabrication designed to sell newspapers" to GossipCop.com.

Prior to Keibler, the divorced actor was linked to various Hollywood stars, including actresses Kelly Preston, Renée Zellweger, Krista Allen, and Céline Balitran.

Clooney divorced actress Talia Balsam after four years of marriage in 1993 and reportedly swore off marriage forever.

"George will ­probably not get married he decided that he could have the career or he could have a family," Clooney's sister, Adelia Zeidler, told Us magazine. "He set goals for himself and has worked hard to achieve those goals. He's very happy with his life."