Who is Hayley Atwell playing in Heartstopper?

As well as plenty of the main cast reprising their roles for season 3, the new season also marks the introduction of a few star-studded new additions including Hayley Atwell.

The Mission: Impossible star is joining the cast along with Jonathan Bailey and Eddie Marsan, but who exactly is Atwell playing?

Read on for everything you need to know about Atwell's character in Heartstopper season 3.

Who is Hayley Atwell playing in Heartstopper?

Atwell will be joining the Heartstopper cast as Nick's (Kit Connor) aunt, Diane.

In the new season, Diane is set to take Nick on a summer holiday to Menorca but has "some tough advice to impart about his relationship with Charlie (Joe Locke)," according to Variety.

Diane is a psychiatrist who may not be a regular appearance for many episodes, but is set to deliver a moment from the original Alice Oseman comics that fans have been anticipating.

Connor revealed more about Diane's inclusion in season 3 in an interview with Teen Vogue, saying: “She offers some advice on how to approach interacting with someone who is going through the kind of issues that Charlie is.

“Very simple and very stripped-back, surface level things, but also incredibly helpful for people dealing with loved ones or friends, people they know, who are going through these issues.”

Speaking about Diane's inclusion in season 3, Oseman told Entertainment Weekly: "At that point, obviously, I couldn't just shove her into the story for that one scene. It wouldn't make any sense.

"So I had to go back, weave in some new scenes, introduce her as a character, help us to understand what her relationship is like with Nick, and then gently lead us towards this final scene that will make sense and that will still have that really emotional impact when we watch it."

Of course, as it's one of the more fan-favourite scenes from the original graphic novels, there was some pressure in including Diane and depicting the scene on screen.

Oseman admitted that it was "definitely one of the bigger screenwriting challenges" in reworking the moment between Diane and Nick. She said: "But I'm really happy with how it all turned out. I think it works out really well and it makes total sense within the episode and it's really emotional."

It also turns out that Atwell didn't audition for the role of Diane, with Oseman saying: "She's a very established actress and we knew that she would be amazing."

Atwell is, of course, known for her roles in Captain America, Agent Carter, Mission: Impossible — Dead Reckoning and Black Mirror, as well as earlier roles in Brideshead Revisited, The Pillars of the Earth and The Duchess.

Read more:

• Joe Locke on Heartstopper season 3, filming sex scenes and famous fans
• Kit Connor on "sweet and tender" sex scenes in Heartstopper season 3
• Heartstopper's Alice Oseman opens up on tackling sex and mental health in season 3

Heartstopper season 3 will arrive on Netflix on Thursday October 3rd. Check out more of our Drama coverage or visit our TV Guide and Streaming Guide to find out what's on.

Check out more of our Drama coverage or visit our TV Guide and Streaming Guide to find out what's on. For more from the biggest stars in TV, listen to The Radio Times Podcast.