London, April 15 (ANI): Katy Perry is reportedly furious with estranged husband Russell Brand after finding out that he had been secretly making sex tapes while they were married.

The 27 year-old singer, who split from her husband of only 14 months in December 2011 allegedly found kinky videos of the British comic performing 'air sex' made while they were a couple.

According to the Daily Star, air sex is a Japanese performance activity to music, which involves filming yourself pretending to have sex with someone fully clothed.

Katy couldn't believe it, a source told the paper.

She found a box of unlabelled DVDs after he'd moved out. She had a look to see what they were and was majorly unimpressed.

Katy had no idea he'd been getting up to 'air sex' and angrily posted them straight back, the source added. (ANI)