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As ASHLEE SIMPSON and PETE WENTZ count down to their wedding this Saturday, they take time out of planning for their big day to talk about how their romance began -- which the FALL OUT BOY guitarist admits wasn't all that easy.

"I was in the 'friend zone' with her for a good solid year," he told L.A. radio station 98.7 Tuesday.

Pete says that although Ashlee flashed him the first time they met ("I lifted my dress over my head," Simpson added), he still had to work hard to cross that line from friend to boyfriend.

"I'd be calling her and following her around like a puppy dog," he confessed.

The pair offically started dating in 2006 and last month announced their plan to wed -- and now there's no confusion where their relationship stands. "I get a look [from her] every time I don't say fiancée," Pete said.