Russell Brand slammed Katy Perry as "vapid, vacuous and plastic" during their marriage.

Russell Brand and Katy Perry

Russell Brand and Katy Perry

The 40-year-old comic visited Africa for Comic Relief in 2010 and admitted the trip had a profound effect on him and made him question his relationship with the 'Firework' hitmaker as his valued changed.

Speaking in new documentary 'Brand: The Second Coming', which was filmed during the couple's 14-month marriage, he said: "The stuff in Africa hit me really hard. I'm associated with the very thing I detest: vapid, vacuous, plastic, constructed, mindless celebrity.

"That's the very sea we're swimming in¿ 'Oh, who's he? He's married to Katy Perry'."

Elsewhere in the film, Russell was seen mocking his wife in a stand-up routine and admitting to friend Stephen Merchant that he didn't think their marriage would last.

He told his pal: "It's definitely good I'm with someone I love.

"But it's not a resolution to anything spiritual... This is my suspicion, that at some point, to be happy, I'm going to have to walk away."

And another scene shows the British funnyman's friend Noel Gallagher admitting he knew their union wouldn't last.

He said: "Russell calls me up once and says, 'What happens when she wants to watch a film and I want to watch another film? It's doing my head in.' I was like, 'Just let her watch the f***ing film.' I knew at that point this ain't gonna go much further."

Katy is said to be feeling very upset and "embarrassed" by the revealing documentary, which director Ondi Timoner has admitted Russell doesn't approve of.

A source told Britain's Grazia magazine: "It hurts like hell for Katy to re-live her painful marriage like this. She feels vulnerable and embarrassed."