Someone thought it would be funny to write "I Heart Rob" on the dirt on Kristen Stewart's truck, a prank referencing her recent split from her "Twilight" co-star, Robert Pattinson. As she got into her car, it Stewart can be heard saying "F**k you" to the paparazzi who appeared to play the prank while they laughed in anticipation of her seeing it, EntertainmentWise reports.

Whether it's unclear whether or not the star caught sight of the "I Heart Rob" written on the bonnet of her blue truck, the star was in no mood to talk to the paps and did not seem amused after leaving a studio in L.A. on Monday, where she was likely preparing for her upcoming role in the film "Camp X Ray," an indie thriller in which she plays a U.S. marine stationed at Guantanamo Bay. The 23-year old kept it simple that day wearing her favorite casual look of a white t-shirt, jeans, glasses and a backwards baseball cap.

Stewart and Pattinson split after four years of dating, having met on the set of "Twilight" while playing the fan favorite fictional couple, Edward and Bella. Though neither Stewart nor Pattinson have confirmed the break-up, they haven't been photographed together for over two months, and multiple insiders have confirmed their split. Pattinson has most recently been spotted cozying up to what many believe is Lisa Marie Presley's daughter, Riley Keough, who starred opposite Stewart in "The Runaways." Pattinson and the mystery girl believed to be Keough were seen at a Beyonce concert together and driving around in Pattinson's truck in L.A.

Pattinson moved out from Stewart's house in May, and sources claimed Pattinson just could not move on from Stewart's affair with her married "Snow White and the Huntsman" directer, Rupert Sanders, a highly publicized scandal last July that may have created a lot of issues for the couple.

Stewart was spotted at Paris Fashion Week sporting two new wrist tattoos, an infinity sign on one wrist and four black lines on the other. Fans have speculated they represent her four-year relationship with Pattinson and her eternal love for him.

Click here to see photos of Stewart leaving an L.A. studio during the "I Heart Rob" prank.

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