Alan, a dachshund puppy - the in-house dog at upmarket Tatler magazine, was killed after getting stuck in the entrance to the publication's offices at London's Vogue House.
It is understood the dog was being walked on his lead by a member of staff when he suddenly rushed towards the door - getting trapped along with a male worker.
Two fire engines were called to the scene and attempts were made to remove the door, but Alan was reportedly declared dead at the scene.
Alan had attracted more than 2,600 Twitter followers through the account @TatlerAlan, where pictures of his life inside and outside the magazine's offices were regularly posted.
The account was a hit in the world of fashion and PR, with Alan's admirers including magazine editors, models and Made In Chelsea's Rosie Fortescue
Alan's owner Jennifer George - an editor's assistant and events manager at Tatler - confirmed the dog's death on Twitter and posted the last photo she took of him as a tribute.
She wrote: "Yesterday my tiny much loved man Alan passed away in a tragic accident.
"Thank you to all that were there to help, all the kind wishes and all who followed @TatlerAlan.
"He was so awesome & so very loved."
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