The proud new mum shared an Instagram photo of her beau as he took to the stage to sing at the Hollywood actor's party.
The 33-year-old Keeping Up With The Kardashians star tweeted the snap from the bustling crowd who had gathered at TAO Downtown in New York.
She accompanied the picture with the caption, "#NYCfor3hours #BabysAsleepNowWatchingMyBaby #2ChainzKanyeQtip."
Rapper 2Chainz joined Golddigger hitmaker Kanye on stage.
The Beach actor Leonardo is believed to have hired the newly-opened restaurant for a dinner with 100 friends.
Kim and Kanye were not the only big names on the exclusive guest list.
Orlando Bloom, Tobey Maguire, Benicio del Toro, Nicky Hilton and Martin Scorsese are also rumoured to have joined in the celebrations which lasted until the early hours.
As well as celebrating his birthday Leo also wanted to raise funds for his Leonardo DiCaprio Foundation. The evening is believed to have raised $3million for the organisation which is dedicated to creating harmony between humanity and the natural world.