The An Education star was a guest at the A Small World event at the Gstaad Palace Hotel attended by media mogul Harvey Weinstein, Meryl Streep's daughter Mamie Gummer and actors Rightor Doyle and Waris Ahluwalia.
The event included a charity raffle of luxury prizes and Mulligan was asked to nominate a charity to receive funds from the event, so she chose the Alzheimer’s Society, a cause close to her heart as her grandmother is living with the condition.
Mulligan appeared to be overcome with emotion when she gave a speech, but the actress insisted she was merely out of breath after stepping outside to call her husband, Mumford & Sons frontman Marcus Mumford, and rushing back in.
She said, "I’m not emotional, I'm just out of breath. I've been running!... Well I am emotional too."
Mulligan previously in a statement, "I am committed to helping Alzheimer’s Society in any way I can. My family and I rely on the help of organisations like Alzheimer’s Society to help us understand the disease and guide us in the care of my grandmother."
The gala raised a total of $95,000 (£58,000) for the Alzheimer's Society, the U.K.'s leading care and research charity for sufferers of Alzheimer's disease and other forms of dementia.
Penelope Cruz's husband was feted by editors of the British version of the publication in its 2011 poll, with Indian-born jewellery designer and actor Waris Ahluwalia and Swedish True Blood hunk Alexander Skarsgard placing second and third, respectively.
Praising the Oscar winner's fashion sense, GQ editors write, "The Spanish actor is the epitome of underplayed style - no wonder he caught Penelope Cruz's attention."
Bollywood icon Shah Rukh Kahn landed at four, while Efron only managed to reach number six and Clooney scrapped into the top 10 at nine.
Supermodel Gisele Bundchen's footballer husband Tom Brady came in at eight.
Meanwhile, Mel Gibson heads up the other end of the spectrum - the Braveheart actor was named the worst-dressed man internationally.
The Karate Kid star Jaden Smith, the 12-year-old son of Will Smith and Jada Pinkett-Smith, and rocker Axl Rose were also criticised for their wardrobe choices.