He passed away in the early hours of this morning at his home in the resort.
In a career which spanned decades, Longthorne performed to millions of people around the world and sang at the Royal Variety Show several times.
He earned an MBE for his charity work in 2012.
A message on the impressionist's official website reads: "It is with the deepest sadness that we have to announce that the nation's beloved entertainer Joe Longthorne MBE passed away peacefully in the early hours of today at his cherished home in Blackpool.
"Joe died in his bedroom, laying in the arms of his devoted husband of 21 years Jamie, with his rosary beads clutched tight to his chest.
"He leaves behind sister Ann and brother John. Our deepest sympathies and condolences go out to Jamie and all the family at this sad time."
Those paying tribute include TV personality Les Dennis, who tweeted: "So very sad to hear that Joe Longthorne has died. Worked with him many times. A supreme talent and a nice man. Thoughts with his family. RIP."
Comedy writer Derren Litten, who created the hit show Benidorm, said he had "always been in awe of his amazing talent".
Cold Feet actor John Thomson and comedian Paul Chuckle both described him as a "great entertainer".
And comedian Tommy Cannon said: "So sad to hear the passing of Joe Longthorne, such a talent with a fabulous voice! You will be missed, Rest in peace."
Longthorne found fame on LWT programme Search For A Star in 1981 and went on to present his own television programme, The Joe Longthorne Show.
After being diagnosed with leukaemia, he received a bone marrow transplant in 2006.
His manager, producer and close friend, Tony Jo has paid tribute. Click below to listen:
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