What did New York's A-list socialite Tinsley Mortimer do with her very glamorous weekend? She hosted Serena Bancroft's birthday party. Who is this Serena Bancroft? She's the towns hottest up-and-coming tween socialite. Everything about this is just insane.

According to Guest of a Guest Tinsley hosted the tea party for Serena and 15 of her littlest pals at the Samantha Thavasa store on Madison Avenue. There wasn't any pin the tail on the donkey at this party. Instead there was some makeovers by a Christian Dior makeup artist, and styling consultations with the Tinz herself. These littlest girls know how to shop!

Just how did Serena Bancroft land such a stellar host for her little bash? Well, she is the daughter of socialite Debbie Bancroft and her banker husband Billy, so that probably helped. As GoaG points out, La Tinz probably wants to get in good with these little rich things now, so that in 10 years she'll still be getting invites to the hot parties. Ms. Mortimer is the face of Japanese handbag maker Samantha Thavasa (and designs several bags for the fashion house each year) so she definitely has a financial interest in bringing attention to the brand, especially among the junior Junior League set.

Since 13-year-old girls (and gays) are CWs target demographic, maybe this is her way of cozying up to an audience she is going to need to be a ratings blockbuster come January. Throw in an appearance guest bartending with Anderson Cooper's boyfriend at gay bar Eastern Bloc and she'll have her base shored up just in time for the premiere.

This might be a make good to Debbie Bancroft, who used to be the muse of polite society's favorite designer Douglas Hannant, until they had beef in 2005, when Hannant chose Tinsley to be his new public face. Burn. Before her reality show airs, Tinsley has to make all the allies she can or else she won't be able to show her face in Southampton ever again. Serving up cupcakes to a bunch of fashion-conscious teens isn't such a bad price to pay.

[Image via Guest of a Guest]