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Keeping it stylish yet casual for rehearsals, stars who will be performing during the American Music Awards this weekend got in their first day of practicing their acts at the Nokia Theatre in Los Angeles.

Rihanna looked like a sexy Greaser, with her shiny black pompadour, sunglasses, plaid shirt and tight dark-wash denim jeans. Natasha Bedingfield was being taken away, a wind machine making her hair go flying.

As for Chris Brown, he was wearing argyle and keeping it simple.

Click any photo to view all 25+ photos from the rehearsals for the American Music Awards in the gallery! 

Keeping it stylish yet casual for rehearsals, stars who will be performing during the American Music Awards this weekend got in their first day of practicing their acts at the Nokia Theatre in Los Angeles.

Rihanna looked like a sexy Greaser, with her shiny black pompadour, sunglasses, plaid shirt and tight dark-wash denim jeans. Natasha Bedingfield was being taken away, a wind machine making her hair go flying.

As for Chris Brown, he was wearing argyle and keeping it simple. Check out all 25+ photos from the rehearsals for the American Music Awards in the gallery!