New York's most eligible bachelor is once again off the market! Topper Mortimer, the financier grandson of a former Standard Oil president (and, yes, Tinsley's ex-husband) said "I do" to designer Tabitha Simmons this weekend, in front of a decidedly well-to-do group of family and friends, including Liv Tyler, Sienna Miller, Tory Burch, Lauren Santo Domingo, and Karen Elson.

The bride, who gave birth to their daughter Violet back in January, wore a vintage-looking lacey number by Dolce and Gabbana to walk down the aisle at the Church of the Resurrection in Manhattan, but changed into a more casual look for their daytime reception at private school kid watering hole, Dorrian's (which happens to be one of Tinsley's go-to spots). Seriously - could this wedding have gotten any more Upper East Side?

Donning a whimsical unicorn headpiece, Tabitha posed alongside her fashionable friends and Topper's siblings, including Minnie Mortimer and Peter Davis, who all seemed pleased to welcome her into the family.

Finishing off the festivities, the happy couple cut into a two-tier, custom-patterned cake designed by one of our favorite dessert goddesses, Chefanie Nass. Click through for an inside look!

[Photo via @tabithasimmons]