By Margi Blash
Updated February 23, 2006 06:00 AM
Credit: Jason Merritt/FilmMagic

She sings, she acts, and she designs – but Mandy Moore, who recently unveiled the spring collection of her Mblem line, insists she’s no J.Lo: “I’m just doing T-shirts,” she says. “It’s more like a hobby to me.” PEOPLE caught up with the 21-year-old (who dates Scrubs star Zach Braff) as she showed off her jersey knits and terry tees and got the scoop on her fashion favorites, her new album and those engagement rumors.

When we see you on the red carpet, you’re always very glamorous. We never see you in T-shirts.
What’s fun about my job is the fact that I get to dress up and get all girly for red carpet events. But it’s too much work to do the red carpet thing all the time – and a lot to live up to. It’s easy to dress casual and wear your flip-flops out in LA wherever we go. I don’t want it any other way.

How do you feel about being grouped with other celebrities who have fashion lines?
I’m not doing an entire line, nor do I really plan to. You won’t see me having a debut at Fashion Week. And no disrespect to the others who have done it. I love Gwen Stefani. I wish I could dress like her. All I know is T-shirts. It’s not brain surgery. It’s just what I wear and what I know.

Are you still pursuing a music career?
I’m hoping that I’ll have a record out by the end of the year. I’m really interested in having a second chance with music. A lot of people remember me in one area back when I was 14 singing about candy and driving a green (Volkswagen) Beetle, which is fine, but I’ve really grown up and my musical tastes have changed. I want the album to reflect that.

What was it like having a guest role earlier this month on Scrubs?
It was so much fun. They are all so awesome and so talented. It felt like a very natural transition from just going there and hanging out to actually being on the show.

Did you ever joke beforehand about being on the show?
I used to joke with them by saying, “If you ever need anyone for a background cross I’m here already. I’ll just walk through the shot.” But I was really happy and flattered because I think so highly of the show. I thought, “You want me?”

How was it working on camera with Zach? Was it uncomfortable?
No. It was totally comfortable. Because everyone knows me and they know that we’re together. It wasn’t as awkward as I would have thought.

There have been rumors that the two of you are secretly engaged. Any truth to them?
I can’t tell you how many people I’ve had call me asking about it. No, it’s not true at all. That’s a big part of my life, and of course I would start by telling my family and friends first. But it’s funny nonetheless. I’ve gotten a lot of congratulations from random people. And I just have to laugh and think, “You believe the tabloids?”