A promo has been released for the Hugh Hefner special Runaway Bride ... a special that was originally intended to film the wedding of Hugh and playmate Crystal Harris, until she called their wedding off five days before it was scheduled to happen.

In it, Hugh gets a visit from former Girls Net Door Holly Madison and Kendra Wilkinson, and he drops a big bomb: that he "screwed up" with Holly!

Madison had wanted to marry Hefner years ago when they were in a relationship, but he didn't want to walk down the aisle.

Hef tells Holly:

    "If you're looking for an explanation [about Crystal], I don't have a clue. I don't really feel ... bitterness ... I never thought I'd get married again. I wasn't planning it. I think I screwed up with us."

Wow! Hindsight is always 20/20 ...

Watch video of the promo after the jump!