Hugh Hefner Announces Engagement to 24-Year-Old Playmate Via Twitter

'This is the happiest Christmas weekend in memory,' the mogul said in his Dec. 25 announcement.

Playboy founder Hugh Hefner, 84, announced his engagement to 24-year-old girlfriend Crystal Harris, a December 2009 Playmate of the Month, with a Christmas Day tweet on Saturday.

"When I gave Crystal the ring, she burst into tears," the twice-divorced publishing mogul wrote. "This is the happiest Christmas weekend in memory."

Hefner, who was the focus of this past summer's documentary release Hugh Hefner: Playboy Activist and Rebel, finalized his divorce from his second wife, former Playboy model Kimberly Conrad, earlier this year.