Emma Watson & Johnny Borrell 'aren't dating'

Emma Watson was spotted partying with Razorlight frontman Johnny Borrell earlier this week - but they're not dating, insists a close pal of the 17-year-old 'Harry Potter' star.

"They were hanging out. Emma has had a boyfriend [ Tom Duckworth, a rugby player] for years," says the friend, dashing rumors of a romance between the pair.

Watson first hung out with Borrell - who has dated actress Kirsten Dunst -  at the Burberry/Vanity Fair portrait exhibition in London Monday.

"She was probably just a bit star struck," the friend tells People.com. "She's usually chaperoned to these kinds of events by her father."

The pair – who were also joined by a female friend of Watson's – then headed on to the PPQ party across town. Borrell and Watson left the PPQ bash separately – the rocker with another girl, then headed to the Dorchester Hotel.

Another source adds that this Watson-Borrell encounter was a one-time thing. "She has never met him before," the source says. "She has not spoken to him since and will likely not speak to him again. "

The insider explains that the couple were photographed together for one simple reason: there were not enough cars to take Watson from one party to another, so she and Borrell, 27, opted to share one.