Channel 4 has announced an additional, extended length episode of Derry Girls.

The special will broadcast later in the same week as the Series 3 finale, scheduled to air on 17th May at 9pm.

Titled The Agreement, it picks up a year on from the end of Series 3 proper and focuses around the Good Friday Agreement referendum, which brought widespread peace and stability to Northern Ireland after decades of bloodshed.

Channel 4 explains: "For this special instalment we return to Derry one year later as the gang prepare for their final year of school. It's the week of the referendum on the Good Friday Agreement and its timing couldn't be any worse as the highlight of the year, Erin and Orla's joint 18th birthday party, threatens to be overshadowed. While the family try to get their heads around the possible outcomes of the vote, the gang realise that they may not be ready for what the future holds."

Lisa McGee, Derry/Londonderry native and the hit sitcom's writer and creator, says:

Like all the very best 90s bands, I couldn't resist ending our farewell tour with an encore for our loyal fans. I'm delighted to say we'll be returning for one extended special - airing in the same week as our final episode. The special deals with the historic and momentous Good Friday Agreement vote, which coincides with the gang's coming of age, they enter adulthood just as Northern Ireland embarks on a new future.

I'm so proud of this show and of our incredible cast and crew and everything we've achieved over the past 5 years. What a journey it's been. I'm so grateful Channel 4 gave me the space to end the stories of these characters that mean so much to me with this special. I really hope the fans love it as much as I do.

Derry people aren't great at saying goodbye so I will instead use one of our native expressions "That's us away now".

Love Lisa McGee, always a Derry Girl

The exact transmission slot of the special is expected to be confirmed next week. Meanwhile, all three series of Derry Girls are currently available to watch on streaming/catch-up platform All 4, whilst Series 3 continues its broadcast run on Tuesday at 9pm.