Britney Spears Dances for the Camera After Saying Her Name’s Now River Red

Britney Spears — or River Red, as she’d like to be called — swapped outfits 3 times Sunday night, dancing to her heart’s content … just days after making the apparent name change.

The singer showed off her signature moves Sunday evening … grooving to 3 separate tracks, complete with costume changes, too.

In her caption, Britney says she can’t act “too kooky or silly like kids” because people will call her “CRAY CRAY” — adding she’s sharing her dancing because “every person I call TAKES 9 RINGS TO ANSWER” … and, “I bet after I post this my security answers after 2 RINGS.”

The freestyle session came after a now-deleted post from last week, showing off a picture of Mars and writing, “I changed my name to River Red” … and saying “don’t underestimate the power of purity.”

She also changed her name on IG to match the announcement.

Fans are scratching their heads at the supposed name change — we are too — but it might simply be her take on Mars, known as the red planet.

There’s also a little known 1998 film called “River Red” — a disturbing family drama — but that seems much less likely.

As we reported, eyewitnesses told us Britney’s hubby Sam Asghari stormed out of a dinner in Woodland Hills this month when she was acting “manic” at their table.