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.

Dave Letterman has a long history of getting flirty with his guests. From Madonna to Drew Barrymore, from Julia Roberts to any one of the countless number of leggy supermodels he's talked to over the years, Diamond Dave has never been one to shy away from batting his proverbial lashes at his guests. Depending on his mood, this flirtatiousness generally takes shape in either a slew of complimentary bon mots or, when he's feeling aggressive, a subtle graze of the knee. But when Gossip Girl Blake Lively showed up on the set on Friday night proclaiming that Dave was one of her "childhood crushes", the sexual tension between the two was not only palpable, it approached the level of David Addison and Maddie Hayes.