Premium editions of Kids, Wait Till You Hear This! cost up to $250 but some say signatures are unnaturally identical

Liza Minnelli fans who bought signed copies of her memoir are seeking refunds because they believe her signature is fake.

Copies of Kids, Wait Till You Hear This! by the American 80-year-old singer were marketed around the world as “hand-signed collectibles”, with premium editions costing up to $250 (£185).

However, some buyers have questioned the uniformity of the signatures and speculated that they were digitally signed by an autopen, a device that replicates handwriting.

“When you see footage of Liza today in her own documentary, she is far too frail to have signed a handful of books this accurately, let alone hundreds,” said autograph collector Gareth Brown, who contacted the Guardian after paying £25 for a signed copy in a Kent bookshop.