The Playboy mogul, Hugh Hefner who split from Kendra Wilkinson in 2008, was among the guests when the model married American football star Hank Baskett in 2009.
He is now planning to walk down the aisle himself this summer after proposing to 24-year-old Crystal Harris over the Christmas holidays in 2010 and Wilkinson admits she was baffled when she didn't receive an invite to the couple's big day.
She tells TV host Jay Leno, "I was a little bit worried, so I put it out there into the universe - the media. You know, sometimes you have to use being a celebrity sometimes, get things out there and be like, 'Where's my invitation? Wink-wink.' "
"I actually got an email from Hef right after that."
Wilkinson reveals she was overwhelmed when she read the message from Hugh Hefner, because he made it clear he will not allow the ceremony to take place unless she is there.
The email, which was held up by Leno on the show, reads, "Dear Kendra. We haven't sent any Save the Dates, but if you can't make the planned wedding on June 18, we'll just change the date. Do you think I'd consider getting married without you being there?!"
"Keep shaking your booty. I love you. See you soon. All best, Hef."
When Leno then asked whether Wilkinson would be attending, she replied, "Yeah, of course... He's where he wants to be in life and I'm happy for him... I'm glad he's doing what he wants to do."