But that wasn't the case at the screening of her latest film.
Instead the British Oscar winner found herself competing for attention as she led one of her more unusual co-stars down the red carpet – Scarlet the pig.
Sun-kissed having recently returned from Mexico, where she has been comforting friend Kate Winslet after her separation from Sam Mendes, Emma was on glowing form as she celebrated the release of Nanny McPhee and The Big Bang in London.
Thankfully the London-born comedienne, who wrote and stars in the sequel, was also joined by other, more compliant, stars from the movie, including American actress Maggie Gyllenhaal.
And the New York-born brunette had nothing but praise for Emma, who retakes the lead role as a nanny who is transformed from ugly to young and beautiful as the children in her charge improve their manners.
"I'm her biggest fan and I know I'm not alone in thinking she is a brilliant genius," said the 32-year-old beauty. "I would like to work with her on everything."
Mum-of-one Maggie stars as stressed parent Isabel Green who struggles to deal with her unruly children and run the family farm while her husband is fighting in WWII.
The role called for her to speak with a British accent, a talent she has perfected alongside her husband Peter Sarsgaard, who gave an incredibly convincing turn in Academy Award-nominated film, An Education.
While neither Dame Maggie Smith nor Ralph Fiennes, who both appear in the family film, could attend the premiere, Rhys Ifans, Bill Bailey and the young stars of show were all there.
Reprising her role as Nanny McPhee for a second time, Emma admitted that, despite her initial appearance, she is growing increasingly fond of the magical governess.
"To me she's someone I'd really like to be," said the Howards End actress.
"Ok, maybe I'd rather not have the warts. But I really would like to be as wise as her and as calm. And the other thing I'd really like to have is a magic stick!"