Doctor Who Carey Mulligan
Carey Mulligan once turned down a regular role on “Doctor Who.” Lars Niki/Getty Images for The Academy of Motion Picture Arts & Sciences

“Blink” is one of the most memorable episodes of “Doctor Who” to date, and its star, Carey Mulligan, has gone on to become an A-list actress. However, she had the chance to return to the BBC America show.

Showrunner Steven Moffat, who wrote Mulligan’s episode, said that he isn’t sure that the sci-fi show was an important role for the actress. “It’s funny but ‘Blink,’ I say immodestly, is a very famous episode of television and yet Carey Mulligan, who was the star of it, I’m almost certain wouldn’t even remember being in ‘Doctor Who,’” Moffat told Radio Times.

“Blink” is very different from the average episode of “Doctor Who.” It barely used series regulars David Tennant and Freema Agyeman and instead focused on Sally Sparrow, a random woman who was dragged into the mystery of the Weeping Angels, often considered the scariest villains in “Doctor Who” history. They are statues who move whenever they aren’t being watched, so “don’t blink” became the mantra of the episode.

While the famous sci-fi show has been on the air for over 50 years, not everyone knows their way around the TARDIS. Mulligan apparently wasn’t very familiar with the Whoniverse, which was in its third season when she guest starred. “I don’t think she was much of a fan, or anything,” Moffat explained.

However, that didn’t stop the producers from offering her a more permanent gig as Sally Sparrow. “They liked her so much, they said, ‘Do you want to be the next companion?’ but she said no. God, she was amazing,” Moffat reflected.

Moffat didn’t indicate when exactly she turned down the gig, but if she was offered the companion job shortly after her episode was filmed in 2007, the role would have been for Season 4. As fans know, a different guest star returned to replace Martha Jones (Freema Agyeman). Catherine Tate, who was introduced in Season 3’s “The Runaway Bride,” appeared as companion Donna Noble in Season 4, and it’s difficult to imagine David Tennant’s final season as the Doctor without the funny gal.

It’s safe to say that Mulligan did alright without being a regular on the cult hit. She has starred in famous flicks like “The Great Gatsby” as well as critically acclaimed movies like “Never Let Me Go” and “An Education.” The latter resulted in a best actress Oscar nomination.

“Doctor Who” will return to BBC America with a holiday special on Dec. 25 and Season 11 premieres in fall 2018.