Nikki Reed -- I'm Lifting My Legs in the Air ... Now That I'm Single

Nikki Reed ditched her wedding ring and tucked her head between her legs Saturday in Los Angeles ... just a day after announcing her divorce.

Reed hit up a yoga studio yesterday in Los Angeles and seemed to be in a pretty somber mood -- makes sense, her and "American Idol" star Paul McDonald just ended their marriage.

The couple says they're still working on an album together ... but they've been living separately for the past 6 months.