Lindsay Lohan has acknowledged her dramatic weight loss over the past few months but insists her worrying disappearing act is just an accidental by-product of “working a lot.”

The actress has looked increasingly skinny lately, and shocked onlookers with her bony frame during a shopping trip last month.

But Lindsay – who currently seems to spend much of her time bickering with girlfriend Samantha Ronson – says she doesn't have an eating disorder.

"I eat. I had my Big Mac yesterday from McDonald's," she told Us at the Matthew Williamson NYC store opening.

"I eat just as much as I always have."

Instead, the Mean Girls star - who raised eyebrows when she shed more pounds than was healthy back in 2005 - puts her skinny look down to "working a lot" and "stress...and lack of sleep when I travel."

She adds, "They've already said everything about me that they can say. And I've never really cared then.

"I'm my own person, and people can say whatever they want. I'm still going to be the person that I am."

See more stars who've found their weight the centre of attention below