Harry, Tom, Dougie and Danny will appear in an episode that will be on our screens in mid-January.
They find themselves at the centre of a drama when a fan is injured whilst trying to catch a glimpse of the boys.
The kind-hearted lads go to the hospital to cheer her up, but when they arrive they soon find out that all is not what it seems.
Casualty approached McFly as they wanted a real band to enhance the storyline that they already had planned.
Fortunately the boys loved the idea and filmed the scenes when they were touring in Bristol.
Hear story
Fame hasn't changed us
Chat about pop
Vote for your fave pop star
