In fact, the 42-year old first found fame more than 20 years ago as a model before she pivoted to acting. Want to know more? Keep reading to find out all about Caitríona's first career as a model...
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Back in 1999, when Caitríona was just 18 years old, she was scouted while collecting money for charity in a supermarket. After dropping out of her drama course at university and working as a model in Dublin for a few months, she caught the attention of a larger modelling agency that whisked her off to Paris.
She subsequently walked runway shows for the likes of Chanel, Givenchy, Dolce & Gabbana, Moschino, Alberta Ferretti and Louis Vuitton. At the height of her modelling days, she was considered to be among the twenty most in-demand models in the world and dubbed "officially Ireland's first supermodel" by the Irish Independent.
Caitríona was scouted at the age of 19 and worked as a model for almost ten years
However, after almost ten years in the industry, Caitríona decided at the age of 27 that she wanted out. Explaining why, she told The Guardian: "Modelling does two things. It gives you a really, really tough exterior and then a really broken interior."
She continued: "Everyone's experience is different, but I know my confidence and my self-esteem when I finished was in the toilet. Being in that for so long can leave you pretty messed up for a little bit."
After pivoting to acting in her late twenties, Caitríona landed the role of Claire on Outlander
After quitting the modelling industry, she decided to pursue acting, and after a small, albeit uncredited, role on The Devil Wears Prada, she landed supporting roles in the films Super 8, Now You See Me and Escape Plan.
In 2014, she was cast as Claire Fraser on Outlander opposite Sam Heughan, a role which has propelled her into superstardom as the smash-hit series has legions of fans all over the world. However, Caitríona has recently opened up about one of the biggest downsides of the show.
She revealed that because filming for the drama takes between nine and 12 months a year, she finds it difficult to fit in other roles. "The beauty of this show is that it's opened a lot of doors. The tough part about it is that we don't have any time to really take advantage of it," she told Vanity Fair.
However, over the last eight years, she's also found the time to squeeze in other projects too, including the film Money Monster, Ford v. Ferrari and Kenneth Branagh's new Oscar contender Belfast, which landed in cinemas in the UK this month.