Lindsay Lohan's rehab bill will be paid for her - if she turns vegan.

The 'Machete' star is reportedly struggling to fund her treatment at the Betty Ford Centre but animal rights organisation People for the Ethical Treatment of Animals (PETA) have offered to step in if she agrees to give up eating meat and animal products.

In a letter obtained by BANG Showbiz, which was sent to the actress through her lawyer, the group wrote: "We understand that you've fallen on tough economic times, so we're writing to you with an offer that we sincerely hope you'll consider.

"PETA will help pay your $50,000 bill for substance addiction treatment if you'll rid yourself of one more toxic substance: meat. As you know, a crucial part of any recovery is showing charity to others. One way to do this is to be kind to animals, the Earth, and your own body. You'll never regret it."

The organisation go on to explain why giving up meat would be good for the actress' health and promise to do whatever they can to ease the change in diet for the star.

The note ends: "California rehabilitation centres have a great reputation for catering to vegan patients too. To help guide your decision, we'll be sending you our new 'Glass Walls' DVD, narrated by Sir Paul McCartney, and our vegetarian/vegan starter kit, which is full of useful information.

"Please let us know if you'd like to take us up on our offer."

Lindsay - who voluntarily entered the facility last month - was told by a court last week that she must stay in rehab until January 3 and the troubled actress has been warned by Judge Elden Fox and her lawyer that this is her last chance at avoiding a long jail sentence.

Judge Fox told the troubled actress - who broke the terms of her probation when she failed two drugs tests for cocaine and amphetamines in September - she would face six months in prison if she provided another positive drugs test before her next court appearance.