Casualty legend Derek Thompson left viewers gobsmacked as he made a surprise appearance in Blue Lights, with fans saying they ‘can’t believe their eyes’

Fans couldn’t contain themselves after spotting Casualty’s Charlie Fairhead in a new role after his poignant departure from the show earlier this year.

Derek Thompson, who played the beloved character, caused quite a stir among viewers with his unexpected appearance on the Belfast-set drama Blue Lights earlier this week, during the second episode of its sophomore season. Derek’s character made a surprise entrance towards the episode’s climax, prompting fans to take to X, previously known as Twitter, to share their excitement about the iconic actor’s unexpected cameo after seeing him as Robin Graham. One thrilled fan wrote: “When you see Charlie from Casualty in #BlueLights,” accompanied by a meme of Leonardo DiCaprio pointing animatedly from a scene in Once Upon a Time in Hollywood.

Another viewer commented: “It’s Charlie from Casualty NOT being Charlie from Casualty #bluelights.” A different fan remarked: “I have watched Derek Thompson as Charlie for so long that it will be strange seeing him in a different role #BlueLights.”

Someone else questioned: “Is that Charlie from Casualty? #bluelights.” Another chimed in: “Episode 2 of #bluelights didn’t disappoint. Marching, Dan Gordon, Charlie from Casualty and this classic.” And another added: “Derek Thompson aka Charlie from #Casualty is playing an absolute blinder in #BlueLights. No mean feat to be one of the most recognisable characters on TV and to switch to a brand new role and make it believable.”

Charlie Fairhead exited the show after being stabbed by a patient (Image: (Image: BBC))

Derek Thompson bid farewell to Casualty in March after an impressive 38-year stint as Charlie Fairhead, having been a fixture in the medical drama since its inception in 1986. The actor, who received a heartfelt tribute from a Loose Women star, was the longest-serving cast member, appearing from the very first episode.

In a nail-biting moment, Charlie was stabbed by a patient, leaving viewers anxiously wondering if he would pull through. Fortunately for fans, Charlie made it out alive and was given a hero’s send-off as his colleagues clapped him out of the hospital following his recovery.

In his final moments on the show, Charlie was seen departing in the passenger seat of a yellow car adorned with a “just retired” sign. Derek announced his exit from Casualty last May, stating: “The time has come for me to hang up Charlie’s scrubs.” The beloved actor, who had a succinct five-word message for his loyal followers, praised his concluding storyline as “some of the best episodes of my career”.

Reflecting on the writing, Derek said: “How [Casualty writer] Michelle Lipton wrote these episodes comes across like she’s written eight plays, taken from so many points of view,” and expressed his belief that “I don’t think there’s another writer who could have done it.”