Ashley Tisdale has been felled by that most dastardly (if at times convenient) diagnosis -- the deviated septum. The "High School Musical" starlet makes a preemptive admission opens up to People about the "rhinoplasty procedure" she endured on Friday.

"Growing up I always knew I had a deviated septum on the right side of my nose, which caused trouble breathing," a still-recovering Tisdale, 22, told the mag on Monday from her Los Angeles home. "The older I got, the worse it got. I went to get it checked out, and the doctor told me the septum was 80 percent deviated and that I had two small fractures on my nose."

That led to last week's five-hour schnoz-fixing op, which the actress says she was so totally dreading.

"I was completely scared," she reveals. "I wasn't looking forward to the surgery at all. I actually had trouble sleeping for a week before."

Still, she somehow found the strength to call People and share her experience, although she confesses, "I'm not feeling great today. It's uncomfortable and I hope this is the only time I ever have to go through something like this."

Ashley takes pains to reiterate that her sniffer procedure was medically necessary, not unlike Jennifer Aniston, who also cited a deviated septum when she sought surgical help in January, and that other Ashlee, as in Simpson, who had the character resculpted out of her proboscis to cure what her dad Joe described as "a problem with her breathing."

"I didn't do this because I believe in plastic surgery. I did this to help my health," she proclaims to the mag. "I literally almost could not breathe out of the right side of my nose."

So, why admit it, other than to get ahead of any before-and-after tabloid and blog speculation?

"I want my fans to know the truth. I'm not someone who is going to act like I had nothing done," says Tisdale, who adds she's not a nip-tuck fan and wouldn't suggest it to anyone. "I just want to be honest because my fans are everything to me."

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