Glee star Dianna Agron sexes up the cover of the September issue of Cosmopolitan which will hit newsstands everywhere Tuesday, August 16th.

In the new issue, Dianna explains why she keeps her personal life private, comparing it to that of Lindsay Lohan.

"It's really sad looking at people like Lindsay Lohan. She's an amazing actress, but you see what happens when people know too much about your personal life," she says.

"They start not being able to look at you the same way professionally. I don't want that to happen to me."

She also reveals her secret to success, what she looks for in a man and one surprising thing that she's never done in bed.

Dianna just dyed her hair pink and was spotted getting in her car on Thursday afternoon with the new streaks of color highlighting her sexy new short hairdo. She's been busy lately, promoting her new film, Glee: The 3D Concert Movie, and getting ready for the upcoming season of her smash hit show, which returns September 20.

See more of Dianna and read more about her in the September 2011 Cosmopolitan, on sale Tuesday, August 16th.