Kanye West serenaded Kim Kardashian at the 2013 Met Ball on Monday night (06.05.13).

The rapper took to the stage at New York's Metropolitan Museum of Art to debut a new track for the annual Costume Institute Gala and made his pregnant girlfriend's heart melt when he spoke out to her in the crowd, dedicating the song to her.

Kanye, 35, said it was ''an ode to Kim ... about how awesome she is.''

Kim, 32, reciprocated her boyfriend's loving comment by snapping a photo of his performance and posting it on her Instagram account, accompanied with the caption: ''Baby you're AWESOME (sic)''

It seemed his song pleased others aside from the raven-haired beauty, who is due to give birth in June.

Other guests at the event, which this year had the theme 'Punk: Chaos to Couture', also enjoyed the entertainment and supermodel guest Coco Rocha admitted she found Kanye's romantic gesture endearing.

A source told UsMagazine.com: ''The audience was jamming to it. Kim was smiling and loving it.''

Coco recalled: ''Kanye telling Kim not to worry what anyone says that she's awesome. Quite touching really.''

Kim continued to document her night with various snapshots, one showing the couple surrounded by a group of fellow-guests standing in front of a mosaic table with the caption: ''Night at the Museum (sic)'', after the 2006 Ben Stiller film.

The reality star's appearance at the 2013 ceremony comes after she was allegedly banned last year by Vogue magazine editor Anna Wintour, who believed Kim ''didn't fit the bill'' for the prestigious ball.

A source previously said: ''Anna hates Kim. Why would she be invited to the event? It is all the biggest stars in the world and Kim doesn't fit that bill at all. The Met Gala is $25,000 a ticket, but Kim couldn't even buy her way in.''