No cold feet this time!

Second time was the charm for Crystal Harris and Hugh Hefner, who tied the knot on New Year's Eve at the Playboy Mansion.

Hugh, 86, and Crystal, 26, were originally supposed to walk down the aisle in June 2011 ... but the blonde beauty called off the wedding before it ever took place.

They reconciled earlier this year and finally married late Monday evening. Hef tweeted out the photo above left after the ceremony, while Crystal shared her own shot of her cleavage-enhancing dress.

Earlier today, Crystal -- who is already going by "Crystal Hefner" on Twitter -- tweeted "Today is the day I become Mrs. Hugh Hefner. Feeling very happy, lucky, and blessed."

This is the first marriage for Crystal and the third for Hugh. Good luck!