London: 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 a daily, 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.