Kanye West irritated Met Ball organizers by "screeching" through his performance.

The "All of the Lights" rapper - who was accompanied to the star-studded annual Costume Institute Gala in New York City on Monday by his pregnant fiancee Kim Kardashian - was one of the musical stars who took the stage at the event, but left organizers and guests scratching their heads by playing several unfamiliar tracks from his new album.

Kanye, who was sporting a bejewelled mask, began his set after Blondie performed some of their most popular tracks, and "started screaming" according to one onlooker. "He played all new tracks that no one knew from his new album, and none of the crowd favorites. His songs were basically screeching into the microphone," the source added to the New York Post newspaper.

Another guest suggested the controversial musician's strange performance would have not been part of the plan for the A-list event. "Every minute of that gala is programmed, and Kanye went off-program and played whatever he wanted," the reveler said.

The Metropolitan Museum of Art insisted, however, that there was no issue with the "Mercy" rapper's performance. "We were thrilled to have Kanye perform," a representative for the venue said.

Kanye, 35, was watched by a crowd of Hollywood's biggest names including Madonna, Anne Hathaway and Eddie Redmayne, but particularly impressed Kim, 32, by dedicating a track to her. Introducing a new song, he said it was "an ode to Kim ... about how awesome she is."