Playboy founder celebrates 85th birthday in Sin City.

SCOTT MONACO/PALMS CASINO RESORT / PLAYBOY ENTERTAINMENT GROUP - A packed house was on hand as Playboy founder Hugh Hefner celebrated his 85th birthday on Saturday (April 09) in Las Vegas with his new fiancee Crystal Harris at the Palms Casino.

In January, Hefner announced his engagement to the 24-year-old Harris. The two are set to tie the knot on June 18.

Hefner, whose magazine was founded in 1953, was divorced from his second wife, Kimberley Conrad in 2010 after several years of estrangement. His first marriage ended in divorce in 1959.

Hefner, known around the world by his nickname, Hef, has championed sexual freedom and civil rights, published stories challenging McCarthyism and the Vietnam War, and backed gay causes and the legalization of marijuana.

Hugh Hefner saying:

"My mother lived to 101. So, we have a good DNA pool here. I have never felt more alive and happier. We are looking to the future."

With a cover featuring a calendar photo of Marilyn Monroe, Hefner put the first issue together in 1953 and it sold 51,000 copies -- enough to finance a second issue -- and led to a multimillion dollar international corporation. Hefner recently took the magazine private.

John Russell, Reuters.