Russell Brand has been shopping for a diamond ring — sparking rumours he is going to propose to girlfriend Katy Perry, people.com reports.

The British comic star was photographed looking at bands at exclusive London jewellers Cartier on Friday with one specific sparkler catching his eye.

A source said, “His face lit up when he saw this one particular diamond ring.

Brand — who is a former heroin addict and alcoholic — said, “She’s ‘The One.’

“I’m a one-woman gentleman now. She’s amazing.”