Russell Brand and his fiancee singer Katy Perry reportedly had their first public tiff at pre-Grammys bash, thanks to the comedian’s odd sense of humour.

The couple was walking the red carpet when Brand started joking about Hitler and drugs, reports the Mirror.

As he was welcomed to the Clive Davis party, he quipped: “Sorry, I thought this was a Clive Dunn event. I thought we’d be here talking about Dad’s Army, I’ve been misled.”

He then started singing the hit sitcom’s theme tune, Who Do You Think You Are Kidding Mr Hitler?

The former drug addict then started on about cocaine.

He said: “Grammys… I know why it’s called that. “That’s how much coke you need to cope with it.” Katy, who caught the end of this exchange, threw a hissy fit.

However, Katy wasn’t pleased. She had planned to use the party to introduce her lover to all of her celeb pals, including Rihanna and Taylor Swift, and wanted him on his best behaviour.

She told him: “Stop it and behave! I don’t want to upset the Grammys, I want one.”

Fortunately, the newly engaged couple was all smiles again by the time they sat down for dinner next to Rihanna.

A source said: “Katy knows that Russell can play up. Before the party she was just hoping her girlfriends got his sense of humour like she does. But Rihanna and Taylor got on with him like a house on fire. It was good to see Rihanna laughing.”