The Toxic hitmaker took a tumble during her Britney: Piece of Me show at Planet Hollywood Casino & Resort last week (29Apr15), and she has been sporting a surgical boot ever since.

Doctors ordered Spears to rest over the weekend to fully recover from torn ligaments, prompting her to axe two shows scheduled for Friday and Saturday (01-02May15) - and now, Spears has postponed Wednesday's (06May15) concert as well.

The news of the latest cancelled gig comes hours after Spears announced she is extending her Las Vegas residency for another three months.

The pop star taped an appearance on comedienne Ellen DeGeneres' talk show, which aired in America on Tuesday (05May15), and spoke about her injury for the first time.

She explained, "I actually wasn't doing anything that hard, I was just kind of bopping around, and I've done, like, eight years' worth of shows, plenty of shows, and I've never actually fell on stage (sic), so it was really kind of embarrassing.

"I got up, and my dancers guided me to keep going. So, not bad. The show must go on."