Kristen Stewart Left Embarrassed After 'I Heart Rob' Prank

The Twilight actress was left red-faced when she arrived back at her blue pick-up truck – find out what happened

Kristen Stewart should have been on cloud nine yesterday – the Twilight actress arrived for what is thought to have been her first day on the set of new movie Camp X-Ray – but was left red-faced after a prank on her blue pick-up truck.

The star had parked her car outside a film studio in LA and when she returned, she was met with the most embarrassing message from a fan – or a naughty paparazzo (we're putting our money on the latter).

The pesky vandal had written the words 'I heart Rob' in huge letters on the bonnest of Kristen's car, and the whole scenario was filmed in order to pick up her reaction. Needless to say, she wasn't impressed.

Kristen walked straight out of the studios, marched over to her car and drove off quickly, muttering some obscenities at the laughing photographers. We have to admit, we'd be pretty mortified if someone wrote our ex-boyfriend's name on our car.

The star looked elated in Paris last week as it was confirmed that the red-headed woman sitting in the passenger seat of his own pick-up truck was not Elvis Presley's granddaughter Riley Keough, after all. It's still unknown who Rob's been romancing, but we imagine Kristen is pretty pleased that it's not her The Runaways co-star.

Here's hoping she found a drive-through car wash on her way home.

ROBERT PATTINSON & RILEY KEOUGH LATEST

KRISTEN STEWART WOWS AT PARIS COUTURE WEEK

ROBERT PATTINSON AND KRISTEN STEWART'S RELATIONSHIP: THE FACTS

Got a tablet? You can now download Marie Claire magazine straight to your iPad, Kindle (just search the store for 'marie claire magazine'), Nook or Google Nexus.