Enter the ninja: Gaga unmasks 'Artpop'

With flying pigs, wigs and a kitchen knife, Lady Gaga debuted songs from her forthcoming album, Artpop,at the iTunes Festival.

The pop star performed seven new songs when she headlined the event at London's Roundhouse on Sunday night.

The Daily Mail reported that one of the more bizarre moments came when the 27-year-old paraded on the stage at Camden's Roundhouse Theatre wearing a customised "ninja" outfit.

It was Gaga's first solo show since she had hip surgery in February.

The concert started with her swinging over the audience in a cage, and involved dancers in hazard suits wearing pig masks and hanging from the ceiling.

The songs included Jewels & Drugs, Sex Dreams and I Wanna Be With You. Artpop is slated for release on November 11.

The iTunes Festival continues throughout September with Elton John, Justin Timberlake and Katy Perry on the lineup.