Cressida Bonas revealed her struggles as someone known for previously dating Prince Harry.
Speaking on BBC Radio 4, the 29-year-old English actress admitted that she felt "pigeonholed."
Cressida dated Prince Harry, who recently tied the knot with Meghan Markle, from 2012 to 2014.
"Especially in this country, I find that people are very quick to put you in a box or put you in a corner and think, 'Oh well, you're that, so you must be that,'" she said during the interview.
Cressida, who stars in the new London play Mrs Orwell, said that being tagged as a royal ex was "incredibly frustrating."
She added: "But you know, it is the way it is... It's making a stand and saying, 'Actually no, this is who I am, and this is what I want to do.'"
Cressida attended Prince Harry and Meghan Markle's nuptials on May 19, 2018. Another ex of Harry's who was spotted in the widely-watched wedding was Chelsy Davy.
Born in Winchester, Hampshire, Cressida came from a wealthy family. She is descended from King Charles II. Her father is entrepreneur Jeffrey Bonas and her mother is 1960s "It girl" Lady Mary-Gaye Curzon.
Aside from being a stage play actress, Bonas is also a brand ambassador for Burberry and Mulberry.
Prince Harry's cousin, Princess Eugenie, introduced Cressida to the prince in 2012.
Cressida and Harry's romantic relationship was largely kept private.
When they broke up in 2014, it was rumored that Cressida had been overwhelmed by the attention she was getting because of being Harry's potential wife.
During Harry and Meghan's wedding, Cressida joined stars from the world of sports and film industry to celebrate with the couple.
Meghan, who previously starred in the hit series, Suits, and Harry exchanged vows at St. George's Chapel, Windsor Castle, nearly two years after they started dating.