Jay Sean enjoys cutting up dead bodies. Really.

The singer - who made his U.S. debut in grand fashion with the No. 1 smash "Down" (co-written by Jared Cotter, who went from Coram to becoming a season 6 semifinalist on "American Idol") featuring Cash Money label mate Lil Wayne - is a former medical student who used to cut up cadavers.

"Deep down inside, I'm a science geek," Sean, 26, said in a recent interview with Mesfin Fekadu of The Associated Press. "I've always been fascinated by the body and the mind." But 21/2 years into medical school, the London-born, Indian-bred performer was offered a record deal and dropped out of college.

He might have made the right choice. After two successful albums released outside the United States, Sean has crossed over with his latest, "All or Nothing."

Didn't you find it hard to balance medical school and music?

I'm a really hardworking person. I think, honestly, hard work is the only way that you'll get anywhere, and this is not an easy job. People think it's easy to be a singer or to be an artist. It's crazy hours and you need a lot of energy and some spirit inside you to do that. But similarly, to be a doctor, you need just the same. Some doctors don't even get to sleep and got to perform open-heart surgery off of, like, 48 hours of being awake - that's hard.

This album isn't your first, though it's your U.S. debut. Do you feel like a new artist?

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Yeah, definitely. The best part is when I'm coming over to America, nobody knows who I am, and nobody cares. I learned that the minute I got to immigration ... he was like, "So what do you do?" and I went, "I'm a singer." He goes, "I haven't heard of you!" ... I realized that, "OK, you know what, I have got a clean slate here, people don't know anything about my history or my background or what I achieved, [so] let me prove myself again." And I love that.

How was your first experience meeting Lil Wayne?

The first day I landed in Miami to meet Cash Money, it's 2 in the morning and when he came in, he came like a hurricane, like this energy he has about him ... he was mad cool, gave mad love, he was like: "Yo, man, I've checked out all your videos and your music and I'm feeling it. Welcome to the family, brother."

Were your surprised to see "Down" do so well?

I was like, "Ugh, are they gonna like it? Is it going to be played on the radio? Are you sure they're going to play it on the radio? You sure?" And then when I heard it on the radio, I was, like, "They're playing it on the radio, this is amazing!" Then I remember we threw a big party when it cracked the Top 100 [on] Billboard. I remember we were popping bottles, and I was, like, "Yeah, Top 100!" ... And then in a few months it's shooting all the way up and I was, like, "Oh, OK, it's getting stupid now, like what's going on?"

What else do you want to do in your career?

I've always been into acting, and I know it's such a cliche: "Oh, wow, he's doing the films. Surprise, surprise." It's like a lot of singers end up doing that, or vice versa. But that's what I used to do in school, I used to write screenplays when I was a little kid, so for me, acting is something I definitely want to go into.

You could play a doctor, right?

Yeah, I could play a doctor. That probably will be my first role, I bet. That or a cabdriver. [Laughs]