London, Jan 05 : Pop star Rihanna has sparked rumours that she is all set to marry beau Chris Brown, after she was spotted sporting a huge diamond rock on the wedding finger.

Rihanna was seen sporting the incredible engagement ring while performing with Brown at the O2 in London.

Although the weather was chilly, she wore fingerless gloves and held her hand to her chest so people could check out the ring.

If reports are to believed Brown popped the question to Rihanna over the New Year.

"Rihanna was wearing the biggest diamond you can imagine," the Sun quoted a source as saying. (ANI)