Harry Potter star Emma Watson's well-to-do folks have banned her from spending time with Razorlight frontman Johnny Borrell.

Chris and Jacqueline Watson "went mad" when they saw photos of their 17-year-old daughter partying with the former heroin addict during London Fashion Week last week.

Emma used the "we're only friends" line on her concerned parents.

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Party pals: Johnny Borrell and Emma Watson chatted at a Vanity Fair party at the National Portrait Gallery on Tuesday night

But it has been revealed that they told Emma "in no uncertain terms that she's not to see Johnny again".

A source said: "They have always kept a strict eye on their daughter and are very protective parents.

"It was a huge shock to see their little girl coming out of a party with hellraiser Johnny on her arm.

"He's 10 years older than her and he's admitted to being a drug addict in the past.

"They're also concerned because his last girlfriend, Kirsten Dunst, ended up in rehab after splitting from him."

Just yesterday Emma wrote on her blog: "I only met him [Johnny] and that was all. Maybe I should stand next to Orlando Bloom and people will say we're dating."

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Sharing a cab: The pair then took a taxi together to the PPQ party at the Dolce nightclub

The couple may not be dating but, if Emma's folks have anything to do with it, they won't be hanging out much either.

The actress, 17, whose Harry Potter character Hermione Granger romances fellow wizard Ron Weasley in the movie, spent a night partying with the Razorlight frontman, 27, at the Burberry party last week.

They were spotted leaving the bash in a taxi together and headed to the PPQ party at the Dolce nightclub on the same night.

Borrell has a history of drink and drug abuse, and once said he was a "smackhead at 16".

He was dumped by Hollywood star Kirsten Dunst, 25, because of his bad boy rocker lifestyle, and she's since checked into Cirque Lodge rehab in Utah.

Emma, has previously dated rising rugby star Tom Ducker, 16.