EastEnders fans were left in shock as they spotted one of the BBC soap's most iconic characters has landed a role in a show packed with A-list stars.

Citadel, which released its third season on Prime Video earlier this month, follows global spy agency Citadel fighting back against crime syndicate Manticore.

But viewers tuning into the episodes, which starred the likes of Priyanka Chopra, Stanley Tucci, Richard Madden and Lesley Manville, were surprised to see one familiar face. 

Watching the third episode of the series, one eagle-eyed fan noticed that the lead police officer attempting to arrest Priya's character Nadia and her counterparts had featured in EastEnders. 

Taking to Reddit, they shared a snap of the on-screen officer, before revealing the character was being played by none other than EastEnders' James Alexandrou. 

James, 41, rose to fame as Martin Fowler on the BBC One series - featuring on Albert Square alongside the Fowler family from 1996 to 2007. 

He went on to present BBC Three's Bizarre Crime before featuring in the likes of Silent Witness and Call the Midwife in cameo roles. 

James plays the 'lead officer' in the third episode of the Citadel, shouting at Priyanka and Richard's characters to drop their weapons and stand down in a stand-off. 

Taking to Reddit to showcase the moment, a fan shared a photo of the actor in action and penned: 'James Alexandrou (Martin Fowler) in Citadel.' 

Another fan penned back to the poster: 'Loving the nostalgia,' as another chimed in: 'He was definitely the best Martin.'

James waved goodbye to the role of Martin in 2007, when the character travelled with Sonia after the death of his mother, Pauline Fowler.

At the time, James said: 'I've decided to leave the show to experience other aspects of my industry.

'Having turned 21, I felt it was a good time to leave. I owe everything to the show and would love to come back one day - that's if EastEnders would have me.'

He took over from Jon Peyton Price - with the part then handed over to James Bye. 

Last year, EastEnders fans watched on as Martin tragically died in the BBC soap's 40th anniversary episode in dramatic scenes. 

When the scenes hit screens, the Citadel actor took to his social media to wave goodbye to the character with a cheeky swipe. 

He wrote to his fans: 'Somehow reckon I’ll still be asked "When are you going back to EastEnders?".'

James Bye also bid farewell to the show in an emotional statement ahead of his final scenes airing, saying: 'Saying goodbye is not easy.

'But after 10 years at EastEnders - and on the night of the show's epic 40th anniversary - the time felt right. It's an honour to leave on a story of this magnitude. RIP Martin Fowler.'

Citadel is available to stream on Prime Video now.