The executive producer of Doctor Who is leaving the BBC to join Channel 4 as Film4's senior commissioning executive.
Piers Wenger joined BBC Wales as head of drama in 2007 and has overseen the latest regeneration with Matt Smith playing the Doctor.
In March Wenger revealed he was taking up a new role as creative leader of key BBC network productions in Cardiff.
Ben Stephenson, controller of BBC Drama Commissioning, said: "I will be very sad to see him go."
"He's been a fantastic colleague and friend - but I know that film is a huge passion of his and this is a great new role for him."
Stephenson said he would be working with Doctor Who writer and co-executive producer Steven Moffat to find a successor in the coming months.
Under Wenger's leadership, BBC Wales relaunched Upstairs Downstairs and oversaw production of the Bafta-winning Sherlock, a contemporary update of the Arthur Conan Doyle character.
Martin Freeman, who played Watson in Sherlock Holmes, was named best supporting actor.
Wenger also saw one of his leading men, Benedict Cumberbatch, nominated for the best actor award for his portrayal of Sherlock Holmes, alongside Matt Smith, who was the first Doctor Who to be nominated. They were both beaten by Daniel Rigby for his portrayal of a young Eric Morecambe.
Keith Jones, director of BBC Wales, paid tribute to Wenger, who leaves the corporation in September.
"He is one of the most talented creative leaders of his generation," he said.
"We are lucky to have benefitted from his extraordinary skills and imagination."
Bethan Jones will serve as acting head of drama for BBC Wales until the end of June when Faith Penhale, from the independent company Kudos, takes up the post as previously announced.
She will oversee the relocation of Doctor Who, along with series such as Casualty, Upstairs Downstairs and the Welsh-language soap opera Pobol y Cwm, to a new BBC Wales drama production centre in Cardiff Bay.