The 5ft 10in, size eight catwalk star underwent an extraordinary transformation to become a look-alike for the Hollywood style siren.
With her bouffant hair and pleated white dress she does her best impression of the actress in the classic 1955 film, 'The Seven Year Itch'.
It contains one of the most iconic images of the 20th century - Monroe standing on a subway grate as her dress is blown above her knees by a passing train.
"I had so much fun being Marilyn Monroe for the day and recreating such an iconic shot," the Daily Mail quoted Stone as saying.
"It was an honour to be asked to take part in such an important campaign. Red Nose Day is such a simple way for everyone to get involved and raise money to help the people that need it most in the UK and Africa," the model said.
She is joined by a host of famous names to launch this year's Red Nose Day campaign, including her husband David Walliams, John Cleese, Alesha Dixon, Amanda Holden, David Tennant and Alexandra Burke.
They're encouraging people to do something funny to raise money for Comic Relief on Red Nose Day - or at the very least buy one of the noses or Vivienne Westwood-designed t-shirts which both raise funds for the cause. (ANI)