Britain's Got Talent winner Pudsey the dog has died it has been reported.

in an emotional tribute on Instagram Ashleigh Butler, who won season six of the ITV talent show with Pudsey announced news that she had made the heartbreaking decision to put him to sleep.

"I can't honestly believe I am writing these words. My handsome man is gone and I don't know what to do without him," she wrote.

"My heart is broken and I don't know how I'm going to get through this. It hurts so much that my handsome man has gone and I don't know how I'm going to get through this. It hurts so much that my handsome incredible Pudsey Bear will never be by my side, where he belongs again."

"We only had 11 years together, but they were the best years ever. He was my one in a billion dog that will never be replaced.

"I don't need to write all of his endless accomplishments on here to prove how incredible he was for me. Sleep tight my handsome man, I love you lots xxxx."

Paying tribute on Facebook Ashleigh's mother Penny revealed he had been battling "acute leukemia".

In a post on Facebook, she wrote: "We, as a family, had to make the hardest decision yesterday to let Pudsey go to sleep. We are absolutely devastated and in shock with how quick this has all happened, and our hearts are broken.

"We would have done anything to keep him with us, even for a little longer, but he didn't have any more time as acute leukemia made us take the heart breaking decision to end his pain."

The pair from Wellingborough in Northamptonshire, came to fame in 2012 after wowing judge Simon Cowell with their Mission Impossible inspired performance.

Royal Variety Performance
Britain's Queen Elizabeth greets Ashleigh and her performing dog Pudsey after the Royal Variety Performance at the Royal Albert Hall in London. REUTERS

Pudsey and Ashleigh had worked together for 11 years and were the first dog act to win the TV talent show.

They performed for The Queen at the Royal Variety Performance and in 2012, Pudsey won a £100k book deal for the publication of his his autobiography. He went on to make his big screen appearance in Pudsey the Dog: The Movie.

News of the passing of the border collie, bichon frise and Chinese crested cross quickly spread on social media prompting tributes from fans and celebrities.

A post on the BGT Twitter feed said: "We are saddened to hear that today we lost Pudsey, a most marvellous winner. Our thoughts are with Ashleigh."

Britain's Got Talent judge David Walliams paid tribute, writing: "Farewell to a very special dog that the nation fell in love with".

Posting a photo of himself with the much-loved dog fellow BGT winner George Sampson wrote: "RIP my little mate, you were and will always be a superstar."