01:00 AM EDT on Monday, July 3, 2006

BY RACHEL LEIBROCK
Sacramento Bee

It isn't easy being Ashlee.

There's the gorgeous, mega-famous older sister. The Saturday Night Live lip-syncing snafu. Being booed at the Orange Bowl. Getting caught on tape -- drunkenly swearing and barefoot -- at a McDonald's.

But Ashlee Simpson, 21, can laugh about it. A few years in showbiz, after all, makes you grow some pretty thick skin.

"It's just a part of the business and I realize that criticism is something that comes with that," says Simpson. "I just shrug it off -- I don't read any of the negativity."

Talking on the phone from Los Angeles, Simpson chatted and giggled at a breakneck pace as she dished on fans, touring and life as Jessica's younger sister.

Simpson launched a full-scale U.S. tour last month where she'll take on everything from tiny nightclubs to gigantic arenas and amphitheaters.

Simpson says she loves both types of venues.

"When you play a small (club), you can see everyone's faces, crammed together and that's always great," she says. "But when you play a big venue . . . you feel like a rock star and it's like, wow."

In case you've managed to shield yourself from all things Simpson, here's a crash course:

The singer first became famous as Jessica Newlyweds Simpson's younger sibling and for acting gigs on Malcolm in the Middle and 7th Heaven.

She got her own major US Weekly-worthy exposure, however, after nabbing an MTV reality series. The Ashlee Simpson Show, co-produced by Simpson's father/manager Joe Simpson, chronicled Simpson's celebrity coming-of-age as she recorded her debut album, fought with her boyfriend and moved into her first apartment.

In October 2004, Simpson was infamously busted for lip-syncing on Saturday Night Live. In the fallout, Simpson (and dad) blamed the debacle on everything from a miscued band and malfunctioning equipment to acid reflux-damaged vocal chords.

But despite the public drubbing Simpson received in the scandal's wake, despite the endless jokes, despite the "Stop Ashlee" Internet petition -- Simpson kept smiling.

That's because, the singer says, she knew her fans had her back.

"They're extremely loyal -- and have been since the beginning," Simpson says. "To know that and to feel that (support) is great."

The real proof of their allegiance, of course, is in the numbers. Simpson's first album, 2004's Autobiography (a mix of bubblegum power pop and Joan Jett-esque rock licks), debuted at number one on the Billboard charts. Meanwhile, the singer's second disc, 2005's I Am Me (which served up more of a Gwen Stefani vibe), has sold just shy of a million copies.

Such success, of course, makes it easier to insulate yourself from the critics.

"I just stay away from it -- I don't listen to any of that," Simpson says.

Not that she hasn't taken something away from all that intense, public scrutiny.

"I think everyone has passed judgment on people, and that would be the only thing I've learned -- not to judge people," she says.

Throughout, Simpson's found her biggest support from her family, especially Jessica.

"We have a wonderful relationship," Simpson says, dismissing an Internet rumor that has her claiming to be "sexier" than her older sister.

"I don't think I've ever said that in my life," she says, laughing. "I would definitely say she's the vixen sister.

"There's no rivalry," she continues, adding that the two rarely discuss business. "We mostly talk about personal things and how our lives are," she says.

As for Simpson's much-maligned dad, the singer knows that critics have had a field day worrying about Joe Simpson's control over his daughters' personal and professional lives.

Ashlee Simpson says she wouldn't have it any other way.

"We discuss everything; I love (my dad's) input," she says. "I can come up with an idea and call him . . . He'll give me advice to expand on it or say, 'Ehhh, where are you going (with that)?' "

Besides, she adds, when the going gets tough, the tough get by on their family's support.

"I would rather have my manager be my dad, who loves me and supports me," Simpson says, "whether I fall on my face or not."

Ashlee Simpson is at the Cape Cod Melody Tent on Thursday and Boston's Bank of America Pavilion Tuesday, July 11.