Davies bought the secondhand 1960s S2 in Barnet, north London, despite not having a driving licence.
Davies said: “I succumbed to the pressure and purchased a second-hand Bentley from Hadley Green Garage.
“My then wife drove it on my behalf because I was unable to drive at the time.”
The car will be sold at Silverstone Auctions on May 13 and is expected to reach £25,000 to £30,000.
The singer, guitarist and songwriter said the car drew attention when he first took it home.
Davies recalled: “We lived in a little semi in Muswell Hill and the neighbours were in shock and awe when they saw this huge black Bentley drive up along the narrow shingle path to the house.
“We subsequently went on holiday in the car to Cornwall, an exotic spot in England which was our family outing with my two daughters in the back with their buckets and spades.”
Davies kept a guitar in the back in case inspiration struck, which it did when he wrote the single which followed the hit Lola.
He continued: “While on our holiday in Mullion in Cornwall I sat in the back seat of the Bentley and wrote a follow-up to Lola, called Apeman, on a Spanish guitar which I carried in the back.”
Davies finally passed his driving test in his mid-40s after five attempts, the first of which was particularly disastrous.
In a previous interview he admitted that he “ran over a lady” in a busy side street, then forgot to put the handbrake on when he got out to help her.
He took his fifth test in Woking, Surrey, and passed despite having been out drinking the night before.