"You see images of a perfect person and say: 'I can never be that'."
But the Peep Show and Fleabag star's tune has certainly changed. Now she tells Vogue: "If someone doesn't like me because of the size of my bum, they can f*** off. Because I'm quite a nice person to be with, actually."
She recalls her own appreciation for women who don't sport typical models' figures, sharing with the fashion magazine: "Once I was in a steam room and there were these two women, big women, who sat there, hot and sweaty, so beautiful - I felt like they were almost goddesses.
"I want that confidence."
Colman, who's acting star as risen as she's gotten older, also spoke up about age discrimination.
"To be the ingenue and to keep working is rare because once people see you as that, they don't like the process of ageing," said Colman, soon to be seen as the Queen in Netflix series The Crown.
"Which is f***ing ridiculous! I grew to my place."