The item of clothing up for grabs is her famous “black sheep” sweater which she wore at a polo match in 1981 when she was engaged to the now King Charles III.

The jumper will be sold by Sotheby’s in its Fashion Icons auction in New York. The auction is to be held in September.

The jumper is expected to fetch between $50,000 to $80,000 (c.£39,000 - £63,000), CNN reports.