The dressing gown was briefly worn by Michael Jackson on 11 September 1988
The late pop star handed it to a female fan in the wings after coming off stage at Aintree during his Bad tour.
The woman said Jackson gave her the black towelling robe as a gift after discovering it was her birthday the following day.
The lot, expected to fetch up to £4,000, will be auctioned at Cottees in Wareham, Dorset, on 21 February.
The woman, who wishes to remain anonymous, said her husband had acted as chauffeur to Jackson during his stay in Liverpool and so she was able to obtain a backstage pass for the concert.
Her crew badge is included in the lot for sale.
'Never been washed'
She had been watching the concert from the wings when Jackson came off stage, wearing the gown that had been put on him by one of his dancers.
She said she had asked for a photograph but he replied "he would give her something better" than a photo.
"With that he took off the black dressing robe and gave it to me", she said.
According to the auctioneers the hooded robe is one of only a few made specially for the dancers on the Bad tour.
It is embroidered with "Michael Jackson - 87 World Tour 88".
It has a pair of dancing legs above a globe and to the front has the name of the dancer Dominic Lucero woven into the top right.
"The robe has never been washed since that night and has been carefully stored since then," the vendor said.
She added she was selling the robe after 23 years so that "someone else can enjoy it".