Britney Spears -- Still As Flexible As She Was in Your Fantasies (PHOTO)

Yep, that's Britney Spears ... and, yep, she can take a bow ... even backwards as this yoga pose proves.

For all you non-yogis out there ... it's called an inverted tip-top bow -- but for your purposes it's just Brit showing us she's still extremely stretchy and bendy at 33.

This pic is most painful ... for Charlie Ebersol to see.