It’s not clear why she was wearing the boot, but she may have been injured while throwing herself into her new fitness kick.

The Toxic singer wore a red crop top and white shorts during the rare solo trip.

It comes just days after Britney’s co-star Taryn Manning said she was ‘worried’ about the star.

The actress, who starred opposite Brit in Crossroads in 2002, shared a snap of herself with the singer and Zoe Saldana on Instagram.

She wore a cast on her left foot (Picture: Coleman-Rayner)She went solo for the outing (Picture: Coleman-Rayner)

‘Not trying to get likes I could care less. I am worried about my friend and co-star,’ she wrote.

‘Too many times we let one go a-stray and never bother to poke our heads around. “Not my chair, not my problem.”

‘Hey, least we aren’t walking into a gas chamber out of left field today #love @britneyspears. For all of you who hit me daily to do something. I hear you now! We care.’

Taryn didn’t mention what exactly sparked her concerns but Britney’s fans have been worried about her since her dad Jamie fell ill and she cancelled her Las Vegas residency last year, while spending much of her time out of the public eye.

Her co-star Taryn Manning recently said she was ‘worried’ about her (Picture: Instagram)

Britney also has an ongoing fight around the terms of her conservatorship after Jamie stepped down as her conservator – a post he’d held since her breakdown of 2007.

She’s also embroiled in a custody battle with ex Kevin Federline after the amount of time she can spend with her children, 14-year-old Sean and 13-year-old Jayden, was reduced.

Kevin was granted a restraining order against her dad for allegedly assaulting Sean back in September.

Britney, who is dating personal trainer Sam Asghari, completed a 30-day stint in rehab in April last year.

Embarrassed: The Toxic singer told Ellen she’s was ‘just bopping around’ when her ankle gave way sending her tumbling to the floor. She credited her backup dancers for helping her get back onto her feet and continue