He'll play retired police officer Robin Graham when Blue Lights returns this spring.
Recently, it was announced that Blue Lights has been given a third and fourth series, before the second series has even aired.
Today, the BBC have announced that Casualty legend Derek Thompson will be star in episodes two to six of series two as retired officer Robin Graham, whose past and conscience catch up with him when trainee solicitor Jen Robinson investigates a decades old case that has dangerous implications for the present
On returning to his hometown of Belfast to guest star in Blue Lights, Derek Thompson, said "I loved the first series of Blue Lights and thought, as did the majority of my friends and colleagues, that it was the best new TV series of last year. I was thrilled and excited {star jumps in the living room} when I got the invitation to take part in series two."
"I was born in Belfast and was equally excited {more star jumps} to travel over to work on the show and pleased to report, having read the scripts, that I'm sure the fans will love the second series every bit as much as the first. Greatly looking forward to it myself as I'm one of them."
In series two, Grace, Annie and Tommy are growing up fast as police officers, but nothing can prepare them for the turmoil they face every day.
It’s a year since the fall of the McIntyre crime gang and the vacuum has been filled by rival gangs, all competing for dominance. Constable Shane Bradley is drafted in to help, but his motivations are unclear. Tommy is dangerously seduced by the world of intelligence policing, while Grace struggles to deal with her son’s absence, and growing feelings for fellow officer Stevie.
As a young loyalist threatens to take over the city, the officers face a major gangland feud, culminating in a violent and devastating confrontation.
Reprising their roles in the forthcoming second series are Siân Brooke as Grace Ellis, Martin McCann as Stevie Neil, Katherine Devlin as Annie Conlon, Nathan Braniff as Tommy Foster, Joanne Crawford as Helen McNally, Andi Osho as Sandra Cliff and Hannah McClean as Jen Robinson. Also set to return are Paddy Jenkins, Desmond Eastwood, Jonathan Harden and Andrea Irvine.
Joining them for the second series will be Frank Blake as new Constable Shane Bradley, along with Seamus O’Hara as Lee Thompson and Seána Kerslake as his sister Mags.
Co-created and written by Declan Lawn and Adam Patterson, Blue Lights is produced by Stephen Wright of Two Cities Television and co-created and co-produced by Louise Gallagher of Gallagher Films with support from Northern Ireland Screen.
Commissioned by Director of BBC Drama, Lindsay Salt and BBC Chief Content Officer, Charlotte Moore, Blue Lights is executive produced by Stephen Wright, Louise Gallagher, Declan Lawn, Adam Patterson and Nick Lambon for the BBC.
Blue Lights returns this spring on BBC One