The long-running medical drama Casualty is set to return to TV screens this Christmas with a special, “innovative” episode, the BBC has revealed. The announcement was made via a cryptic teaser trailer following the season finale, which aired on BBC One on Saturday.

The BBC teased that the upcoming Christmas special will “celebrate the gift of giving” and will be presented in a “format-breaking” way, promising something different for fans of the show. A teaser image accompanying the trailer showed a hospital ward blanketed in snow, with a fluorescent jacket lying on the ground, adding to the mystery surrounding the episode.

Casualty, which has been on British television since 1986, holds the title of the world’s longest-running medical drama. It follows the lives of staff and patients at the fictional Holby City Hospital’s A&E ward. The most recent season has been divided into four mini-series, including Driving Force, A History Of Violence, Breaking Point, and Storm Damage.

This season also marked the departure of Charlie Fairhead, the show’s longest-serving character, played by Derek Thompson for 38 years. Charlie’s emotional exit was featured in an episode named Charlie, in which he drove off in a yellow car with a sign reading “Just retired.

Despite the departure of its iconic character, Casualty continues to thrive. The series has won six BAFTAs, been nominated for 18, and is in the running for this year’s National Television Awards in the serial drama category.

The latest series of Casualty is available to stream on BBC iPlayer. Fans can expect more details about the Christmas special in the coming months.