Actors Jonathan Bailey, Hayley Atwell and Eddie Marsan have joined the cast of Heartstopper series three.

Based on the popular graphic novels by Alice Oseman, the Netflix show follows the lives of school boys Charlie Spring (Joe Locke) and Nick Nelson (Kit Connor) as they begin a relationship.

After the LGBTQ+ series launched on Netflix in April 2022 it developed a huge fan base and in 2023 Connor, 20, won the leading actor gong at the Royal Television Society (RTS) Awards for his role playing Nick.

In series three, Bridgerton star Bailey, 36, who won a Critic’s Choice Award this year for his role in LGBTQ+ drama Fellow Travelers, will make a cameo appearance as Instagram-famous classicist Jack Maddox.

Meanwhile, Atwell, 42, known for playing Peggy Carter in the Marvel Cinematic Universe (MCU), will join the Nelson family as Nick’s aunt Diane, while Back To Black actor Marsan, 55, will portray Charlie’s therapist Geoff.

Oseman, 29, said: “I am incredibly excited to be welcoming three new cast members to the Heartstopper family.

“Hayley Atwell joins the Nelson family as Nick’s aunt Diane, who takes Nick on a summer holiday to Menorca and has some tough advice to impart about his relationship.

“Eddie Marsan will be portraying a beloved character from the graphic novels: Geoff, Charlie’s wise and straight-talking therapist.

“And lastly, Jonathan Bailey will be making a cameo appearance as Jack Maddox, an Instagram-famous classicist and celebrity crush of Charlie.

Mission: Impossible – Dead Reckoning Part One UK premiere
Hayley Atwell also starred in Mission: Impossible – Dead Reckoning Part One (Ian West/PA)

“It was an absolute joy to see Hayley, Eddie and Jonathan’s talent alongside our existing cast, and I can’t wait for the Heartstopper fans to meet these new characters.”

Oscar-winning actress Olivia Colman played Nick’s mum in the show but told US outlet Forbes in March that she would not be returning for series three as she “couldn’t fit it in”.

The series will follow Nick and Charlie as the summer holiday comes to an end and the pair start to think about their university choices.

Returning members of cast include William Gao, Corinna Brown, Kizzy Edgell, Tobie Donovan and Doctor Who’s Yasmin Finney.

The eight-episode series will arrive onto Netflix in October.