Comedian Russell Brand and girlfriend Jemima Khan have fuelled rumours that they are engaged after she was spotted wearing a diamond ring.

Jemima, 40, was seen wearing a diamond ring yesterday in east London and she apparently looked very happy, reported Daily Mirror. "It looked like an engagement ring. It was very pretty and classy. She looked very happy," the source said.

The 38-year-old funnyman, who fuelled dating rumours with Jemima last year, had earlier said that the journalist made him a "changed man". Jemina has two sons with former cricketer Imran Khan. She also dated actor Hugh Grant.