Britney Spears is plotting to subtly retaliate against ex-boyfriend Justin Timberlake's Cry Me a River video in her new promo, Toxic.

The Lucky pop superstar has admitted Timberlake's video, which featured him stalking a Britney lookalike after she cheated on him, upset her - and though she's been keen to distance herself from the controversy it caused, she's making sure he gets the message in her new video.

In Toxic, Britney plays a femme fatale looking to kill her cheating ex, played by The Ring star Martin Henderson. Model Tyson Beckford also appears in the video as Britney's assistant, who helps his boss get hold of a poison potion to kill her lover.

Sexy Britney also plans to excite fans with her outfits in the video - she wears an air stewardess costume for one scene, a black catsuit for another and nothing but pasted-on diamonds for a penultimate scene.

Britney Spears begged designers to airbrush photos for her upcoming world tour - because she looked too fat in them.

The Onyx Hotel Tour snaps reportedly featured the singer looking bloated and chunky, until they were digitally slimmed down to resemble her trademark svelte body.

And Britney's personal trainer Bobby Strom has exposed several sources behind her fluctuating weight, including her mom Lynne's home cooking.

He says, "Her mind has not been in the right place for working out. She's had lots of stuff to get sorted in her head and her personal life lately. But I think that she's over it and back on course, mentally and physically. I'm sure I'll be seeing her again soon."

"She's fond of her mom's food but it tends to be carb heavy and calorific. I've told her to cut out barbeque sauces and gravies, and eat more protein - especially on tour. She also needs complex carbs such as brown rice, veg and wholegrain breads."

A source tells Britain's STAR magazine Britney, 22, was devastated by her appearance in the photos, and complained to her promoters, "I look like a blimp, so do something about it. I need to look perfect - better than perfect."