Hugh Hefner and Crystal Harris have tied the knot.

Just 18 months after the 26-year-old blonde called off their wedding last year, Hefner and Harris were married in a lavish ceremony at the Playboy mansion on New Year's Eve.

Hefner (86) shared a picture of himself and Harris at the altar, tweeting: "'Crystal & I married on New Year's Eve in the Mansion with Keith as my Best Man. Love that girl!"

Earlier in the day, Harris – who had already changed her Twitter name to "Crystal Hefner" – tweeted: "Today is the day I become Mrs Hugh Hefner. Feeling very happy, lucky, and blessed."

Hefner – who reunited with Harris earlier this year – recently revealed that he plans to stay married to the aspiring singer and mode until he dies, and insists that their 60-year age gap is not an issue.

He tweeted: "The dramatic age difference between difference & Crystal & me really doesn't matter. Whatever time I have left, we want to spend together."

Hefner has been married twice before - to Mildred Williams from 1949 to 1959 and Kimberley Conrad from 1989 to 2010.