Not only will Madison be a bridesmaid, but she "assumes" her and Wilkinson's costar, Bridget Marquardt, will also participate in the wedding.
"I'm really excited about it," Madison told PEOPLE before hosting Thursday's third anniversary party for the Chicago hotspot RiNo. "If she needs any help planning, I'll pitch in. It's going to be a really great event – it's going to be amazing."
And while Madison has yet to meet Wilkinson's fiancé, the Philadelphia Eagles wide receiver will still need her stamp of approval.
"Ever since they met, I've just seen a difference in Kendra: she's matured, she's a more compassionate, considerate person," said Madison. "She's just grown up so much and just to see what he brings out in her is just amazing."
Loves Criss AngelShould her invitation to the wedding at the Playboy Mansion read "plus-one," Madison can bring her new boyfriend, illusionist Criss Angel, with whom she says she's "in love."
"I'm really, really happy," Madison gushed. "He's really, really fun, really sweet – he's so amazing to be around."
Though looking forward to her first Thanksgiving with Angel, Madison admits that the one potential damper in the new relationship was a possible bad reaction from Hugh Hefner.
"I thought I'd be fired, but I wasn't," she said with a laugh. Of the Playboy founder, she said, "We'll always be close friends, and we're always very supportive of each other's decisions – and we still work together well, thank God."
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