Comic-Con Nerd HQ: Nathan Fillion and Adam Baldwin Kiss Zachary Levi for Charity (VIDEO)

In case you missed it, this happened over the weekend at the nerd-friendly, all-around pop culture convention in San Diego.

Castle and Firefly star Nathan Fillion was a fixture at Zachary Levi’s Nerd HQ events throughout Comic-Con 2012, and he took the initiative to heat things up at this year’s “Conversations for a Cause” panel.

In order to raise money for charity, Levi announced that last year he offered $100 for a kiss on the cheek. But this year, with one woman donating $1,000, the Chuck star was prompted to dip the donator center stage and plant a kiss right on her lips.

This being too much for Fillion to handle, he spontaneously threw a handful of cash at Levi and offered him a passionate smooch for the cause. And seeing as cult hit Firefly was celebrating its 10th anniversary, Adam Baldwin was on hand to share in the joy and follow suit.

Fillion later took to Twitter to address the event:

Did I kiss @ZacharyLevi on the mouth?? C’mon. That did not happen. Oh, wait…

— Nathan Fillion (@NathanFillion) July 15, 2012

Check out our What’s Trending coverage LIVE from Comic-Con 2012, including Shira Lazar’s interview with Zachary Levi from Nerd HQ!