Britney Spears is working "really hard" to lose weight after accusing photographers of editing images to make her appear heavier.The singer uploaded a video of herself lifting weights and doing squats to her Instagram page on Monday and captioned it: "I've been working really hard to lose weight ....

and for me, 3 pounds (1.3 kilograms) is like 7 pounds (3 kilograms) it's a lot.

I don't like doing too much cardio.

My body has muscle memory, cus (sic) I used to be a gymnast and I can bulk up ....

so I like isolated movement." Britney's boyfriend Sam Asghari was quick to comment on the video, which showed the mother-of-two working out under a tree, writing: "Perfect as it can be! Lioness always inspiring the world." Describing how she hopes her workout gives her a body like her fitness trainer beau, Britney added: "The key to my workout is repetition, but that gets boring, so I have a booklet I've made with all my favourite exercises.

I usually wear headphones...music takes me away.

I know I don't look perfect here, but I'm working on it.

Hopefully one day I can give my boyfriend's abs a run for their money !!!!" The Toxic star's workout post comes just a week after she took to Instagram to share her suspicions about photographers doctoring images of her, following the publication of snaps of her and Sam on a beach in Miami, Florida.

"Yesterday, I went swimming," the 37-year-old told her fans.

"I look like I'm 40 pounds bigger than I am today.

This is how I am right now, and I'm skinny as a needle.

You tell me, what is real?" Representatives for the photo agency MEGA, the firm who released the photos, took issue with the hitmaker's claims, calling them "ludicrous".