Radcliffe, 18, and Watson, 17, tried to avoid attention as they huddled together in a London beer garden on Valentine's night, The Mirror reports.

"(Watson) kept looking over her shoulder nervously as if she didn't wanted to be recognised," an onlooker was reported as saying.

"When people started to notice the couple and began pointing, she wrapped her scarf around her head so only her eyes were peeping out."

The pair giggled and chatted the night away before leaving close to closing time.

"They then left the pub, heads together and whispering, and headed in the direction of Daniel's home nearby," the onlooker said.

The pair have been close friends since meeting on the set of Harry Potter and the Philosopher's Stone seven years ago.

Radcliffe recently split with Equus co-star Laura O'Toole, 22.

Last week, Watson was rumoured to be dating bad boy Razorlight frontman Johnny Borrell, who is 10 years her senior.

Radcliffe gained access to his fortune — believed to be worth close to $50 million — when he turned 18 last July.