Hollywood siren Megan Fox, who was recently voted Sexiest Woman In The World by FHM magazine, is set to play Mother Teresa.

But devout Catholics need not fear, it is not a serious biopic.

Saintly? Megan Fox plays Mother Teresa in a movie within a movie

She stars in How To Lose Friends and Alienate People as upcoming actress Sophia Maes, who lands the lead role in a movie-within-a-movie on the life of the famous nun.

Fox appears alongside Simon Pegg and Kirsten Dunst in the film, which is based on Toby Young's memoir of the same name.

Siren: The actress stars in How To Lose Friends and Alienate People

Meanwhile, the 22-year-old has been ordered to put on weight for her role in the second Transformers movie.

The Angelina Jolie look alike said: 'I had to put on weight. I’d lost a lot of weight and got really scrawny, but I was told I had to put on size for Transformers because Michael doesn’t like skinny girls.'

'I have a serious sugar tooth, so now I eat red-velvet cake before I go to bed every night, and if you eat meals later, you’ll put on weight faster, so I had dinner at 10 p.m.'

Action hero: Megan has been ordered to put on weight for her role in the next Transformers movie