DEADLINE.COM EXCLUSIVE: This is a shocker: One of The Good Doctor’s most popular cast members who has been on the show from the start, Antonia Thomas, is departing after four seasons. The ABC medical drama will bid farewell to Thomas as a series regular — and to her character, Dr. Claire Browne — in the Season 4 finale, which airs tonight at 10 p.m. It concludes a two-part closer, in which the team from the San Jose St. Bonaventure Hospital are on a surgical mission in Guatemala.

In an interview with Deadline, Thomas spoke about her decision to leave the series before the end of her contract, hinting that the size of U.S. broadcast orders was a factor as she is looking to “explore different creative opportunities.” She also indicated that she would love to reprise her role as a guest star in the future.

The Good Doctor, created and executive produced by David Shore based on a Korean format, was the first major U.S. series for British actress Thomas. She quickly emerged as a female lead opposite fellow Brit Freddie Highmore. Her compassionate and kind Dr. Browne, a fan favorite, was the first resident — or doctor — at the hospital to embrace Dr. Shaun Murphy (Highmore) besides his mentor Dr. Glassman (Richard Schiff). Four seasons in, Claire has remained a close friend and confidant of Shaun’s, helping him with advice on everything from medical predicaments to romantic conundrums.

Over the past two seasons, Claire went through a lot of heartache. In Season 3, her abusive mother came back into her life. Just as the two reconciled, her mom died in a drunk driving accident. In the Season 4 premiere, Claire was left devastated when Melendez (Nicholas Gonzalez) died shortly after he and Claire professed their love for one another.

As her arc was coming to a close, things started to look up for Claire. Her estranged father recently reconnected with her and, after some internal struggle on her part, the two made amends and she let him back into her life.

With Gonzalez leaving at the start of Season 4 and Thomas at the end, The Good Doctor is promoting two recurring players to series regulars next season, Noah Galvin (Asher Wolke) and Bria Samoné Henderson (Jordan Allen).

Thomas, who starred in UK series Lovesick, Homefront and Misfits before landing The Good Doctor, has been branching out. She teamed with fellow The Good Doctor cast member Chuku Modu, who departed after the first season, as the two wrote, produced and starred in the 2020 film Freedoms Name Is Mighty Sweet.

Here is a spoiler-free portion of Deadline’s interview with Thomas, in which she reflects on her four years on The Good Doctor, reveals who she thinks would pick up the mantle of the show’s moral compass from Claire and talks about what she plans to do next. We will update the Q&A with the rest of her answers, in which she discusses tonight’s finale and shares sweet behind-the-scene details about filming her last scenes as well as her vision for Claire’s future, after the episode airs tonight.