Well, so much for that: Hugh Hefner confirmed Tuesday that his wedding to 25-year-old model Crystal Harris has been called off.

"Crystal has had a change of heart," he said via Twitter.

Harris also responded to reports on her personal website, saying, "After much deep reflection and thought I have decided to end my engagement with Hef. I have the utmost respect for Hef and wish him the best going forward. I hope the media will give each of us the privacy we deserve during this time."

So what exactly caused the last-minute cancellation? Though unconfirmed, sources for TMZ claim Hefner, 85, and Harris had a "nasty argument" last weekend over the phone, prompting Harris to pack her bags and leave the Playboy mansion.

The couple was set to marry this Saturday, June 18.

Sad news all around, though, given Hef's history with women, we're guessing he'll bounce back pretty quickly.

[TMZ]