Alex Beckett has died suddenly.
His other TV roles included Seth in I Live With Models and, most recently, Jonno in The End Of The F***ing World. He had recently completed filming on new Channel 4 sitcom Stath Lets Flats, which will be aired later this year.
His agent Gavin Denton-Jones released a statement saying: "We're deeply saddened by the loss of Alex - a wonderful man and a hugely talented actor. Our thoughts are with his family and we kindly ask that their privacy be respected at this difficult time."
Shane Allen from the BBC has paid tribute to his talents: "We're all incredibly crushed to hear of Alex's untimely death. He was a very prolific, versatile and much admired comedy star whose role as Barney Lumsden in both Twenty Twelve and W1A was a key ingredient of their success. We think of him fondly and our hearts go out to his family and friends at this painfully sad time."
The circumstances and cause of Beckett's death are not currently known. He was born in Carmarthenshire, south west Wales, in 1982 and graduated from the prestigious Royal Academy of Dramatic Arts in 2003.
Beckett has been starring as the character Waitwell in The Way Of The World play at Donmar Warehouse since the end of March. The venue, which has now cancelled this week's performances, says: "We are deeply shocked by the tragic loss of our dear friend and brilliant actor Alex Beckett, a much-loved member of The Way Of The World company. Our thoughts are with his family and close friends at this incredibly sad time.
"Everyone at the Donmar and The Way of the World company are completely devastated by this terribly sad news. We have taken the decision to cancel the remaining performances this week, as a mark of respect to Alex, and to give some time to the company, who all loved Alex as a fellow actor, and a friend."
Beckett's W1A co-stars have taken to social media to pay tribute to him: