The 28-year-old actress was joined by her boyfriend Josh Groban.
This was the first time that Kat and Josh have attended the huge star-studded party as a couple.
The day before, Kat had something else on her mind, besides from the award show.
“My next endeavor is to open my romantic seafood restaurant, ‘That’s A Moray’,” Kat tweeted.
FYI: Kat is wearing a Gemy Maalouf gown.
10+ pictures inside of Kat Dennings and Josh Groban at the Vanity Fair Oscar Party… More Here! »