Harriet Marston Slater (born 18 February 1994) is an English actress. On television, she is known for her roles in the DC Universe series Pennyworth (2019–2022), the MGM+ period drama Belgravia: The Next Chapter (2024) and the Starz prequel Outlander: Blood of My Blood (2025). She was named a 2023 Bright Young Thing by Tatler.
Early life Harriet Marston Slater was born on 18 February 1994 in Leicester, England, and raised there. Her extended family were active in amateur dramatics. She joined a local youth theatre group, the Little Theatre, at six. She found acting a stress-reliever for anxiety. Slater has mentioned Lindsay Lohan and Jane Fonda as inspirations. She graduated with a Bachelor of Arts in Acting from the Guildford School of Acting in 2016.
Career After graduating from drama school, Slater began her career in regional theatre, making her professional debut in The Man with the Hammer at the Theatre Royal, Plymouth in 2016. She next appeared in the Royal Shakespeare Company production of Phil Porter's Vice Versa at the Swan Theatre in 2017. She also appeared in The Secret Seven at Storyhouse.
Slater made her television debut when she was cast as Sandra Onslow in the DC Universe series and Batman prequel Pennyworth, which premiered on Epix in 2019. After playing a recurring character during the first season, she joined the main cast for the subsequent two seasons. She made her feature film debut in the 2020 indie fantasy film Emily and the Magical Journey. In 2023, she had a small role in Indiana Jones and the Dial of Destiny.
In 2024, Slater starred as Clara Trenchard (née Dunn) in Helen Edmundson's period drama Belgravia: The Next Chapter for MGM+. In February 2024, it was announced that she had been cast as Ellen MacKenzie in the Outlander prequel series Outlander: Blood of My Blood. She appeared in the films Tarot (also known as Horrorscope) and True Haunting.
Personal life As of 2023, Slater is in a relationship.
Filmography
Film Year Title Role Notes 2020 Emily and the Magical Journey Kayla 2023 Indiana Jones and the Dial of Destiny Fran 2024 Tarot Haley 2026 Fall 2: Deadpoint Jax Hunter
Television Year Title Role Notes 2019–2022 Pennyworth Sandra Onslow Recurring role (season 1); main role (seasons 2–3) 2020 All Creatures Great and Small Brenda Episode: "A Cure for All Ills" 2024 Belgravia: The Next Chapter Clara Dunn / Clara Trenchard Main role 2025 Outlander: Blood of My Blood Ellen MacKenzie Main role
Stage Year Title Role Notes 2016 The Man with the Hammer Jodie Theatre Royal, Plymouth 2017 Vice Versa Meretrix / Voluptua (understudy) Swan Theatre, Stratford-upon-Avon The Secret Seven Janet Storyhouse, Chester
References
External links
Harriet Slater at Spotlight