David Letterman made an honest woman of his sweetheart, and this is how the gods reward him: Blake Lively, still nursing a childhood Letterman crush, tempted the Late Show host with a threesome.

Sure, Lively was joking about a polygamist marriage between her, Letterman, and Julia Roberts, but the electricity between the Gossip Girl star and Letterman as strong and real as that time one year ago when Lively said Letterman was in the same league as Leonardo DiCaprio, and he kissed her hand.

The on-air flirtation this time didn't quite reach Letterman-Drew Barrymore levels, but between the thigh groping, chin touching and hair twirling, Letterman was primed to laugh at Lively's dog story like it was told by Robin Williams.

Lively made sure Letterman knew she was free — some sort of vacation — in a week. One week. Seven days.

Or about how long Letterman has been married, and how long he'll be taking cold showers for.

Send an email to Ryan Tate, the author of this post, at ryan@gawker.com.