In March 2022, HBO and Warner Bros. announced a prequel series to the IT franchise. The prequel will be titled, "Welcome to Derry". The director of the two earlier films, Andy Muschietti, will work as an executive director on the series with his sister, Barbara Muschietti.
The show is filming in Port Hope, Ontario, Canada.
The show began filming in May 2023 despite the 2023 Writers Guild of America Strike taking place around the same time. Writing for the show was already completed before the strike.
The show is a prequel series to director Andy Muschietti's It (2017) and It Chapter Two (2019). It explores the origins of Pennywise/It.
Bill Skarsgård, who portrayed Pennywise/It in It (2017) and It Chapter Two (2019), was initially not part of the show's cast when filming began. In a 2023 interview, when asked if he would return as Pennywise, he stated he was hesitant due to how much work it takes to portray such a character. Eventually, in May 2024, it was announced that Skarsgård had returned to the role for the show.