NEW VIDEO: ASHLEY SIMPSON

Ashlee Simpson: pop star, celebrity girlfriend, devoted sister ... mental patient? That's right – the youngest Simpson sister dons a straitjacket in an arty new video that debuted Wednesday. After spending the last year quietly recording her third album and tagging along on boyfriend Pete Wentz's band Fall Out Boy's tour, Simpson, 23, sat down with PEOPLE on the set of her video for her Timbaland-produced single "Outta My Head (Ah Ya Ya)." "I went to [Salvador] Dali's museum in Paris and was really inspired by the surrealism," she explains on the second day of the Burbank, Calif., shoot. "I wanted to do an ambitious video [where] you basically go into another world and never know what's real. I am five different people in the video. The real me is in therapy and then it all turns into a painting. For me it's like an art piece. Its fun to do all of the crazy hair and make-up changes and different characters." Reminiscent of Madonna's '80s hit "Burnin Up." Simpson's looks in the video are all over the place– from a mental patient to a computer-generated head. She even revisits her old self: "There will be a black wig in [the video]. Going back to the old, dark haired me," she laughs. "That's the great thing about doing videos – you get to go into whatever world you want."

No Where to Run

The track is Simpson's "leave me alone" anthem. "The song is basically everybody's opinions and voices and it's like 'get out of my head!' You have to have your own creativity and place," she explains. "Some people get it from a guy or mom. At the end of the day you're like 'Ahhh! Everybody stop!' " Like Britney Spears in her new "Piece of Me" video, Simpson also goes on the run from the press. "I'm being chased by paparazzi, and whatever [else] that's chasing her in her head. She's basically on the run." As for the rest of Simpson's as-yet-untitled album, due in March, "My record is about having a good time. It's not too serious or anything," she says. "There's a bit of cheekiness. It's more about having fun."