Hugh Hefner and Crystal Harris became engaged Christmas, RadarOnline.com has confirmed.

The legendary Playboy founder went to his Twitter page to announce the happy news after giving his stunning girlfriend an equally stunning ring.

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"When I gave Crystal the ring, she burst into tears.  This is the happiest Christmas weekend in memory," the 84-year-old father of four Tweeted.

"Yes, the ring I gave Crystal is an engagement ring.  A very merry Christmas to all."

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Girls Next Door star Crystal, 24, was Playboy's Miss January, and has been Hef's one-and-only for some time.

They haven't yet said when they'll walk down the aisle.

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Congratulations to them both!

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