Her father may be the legendary lead singer for Aerosmith, but actress Liv Tyler hardly behaves like some ass-kissing rock groupie around pa Steven Tyler. "I love my dad, but I'm definitely critical of him sometimes when his pants are too tight or [when] he says silly things," she tells TV Guide Online. "I try to be supportive, though."

In fact, Liv couldn't help but gush when she first heard her dad's new album, Just Push Play. "I couldn't believe how brilliant [it was]," she marvels, adding that she also complimented her old man on his performance at the American Music Awards earlier this year. "I thought he looked beautiful, and he had a great suit on. I left him a big congratulatory message on his cell phone. He told me that hearing it made him cry."

Liv isn't revealing how her father reacted to her sexy turn in the offbeat black comedy One Night at McCool's, which opens April 27. In one scene, the Armageddon star scrubs down a car wearing nothing but a clingy transparent dress. "The director showed me this scene of a woman washing a car in [the 1967 Paul Newman pic] Cool Hand Luke," she remembers. "It was incredibly provocative and all these men watching her were going crazy. I thought, 'I can do that.' So they put me in front of a really dirty car with a bucket and hose and I went for it.

"I also get to suck on [co-star] Matt Dillon's finger," she adds with a laugh. "When I saw that scene I was like crouching down in my seat because I don't think of myself that way."

Liv might have an easier time picturing herself as an ugly duckling — which is what she felt like during much of her youth. "When I was a kid, most of the boys just came up to my shoulder," confesses the 5'10" beauty. "I was the big oaf in the class. Now, I love being tall, even though sometimes I wish I was short and cute. Then, somebody could just scoop me up in their arms and carry me away."

The guy who's swept Liv away in real life is her fiancé Roy Langdon, frontman and guitarist for the British rock group Spacehog. "He's a couple of inches shorter than me, but when I take my shoes off everything is fine," she says. "Since we got engaged, I've been floating down the street everyday with a smile on my face."