GLASGOW— A Glasgow-based art collector who recently bought a Joan Eardley drawing has discovered a painting by the artist hidden inside the frame, which is worth more than four times the price he paid, reports the Herald (Scotland).

After purchasing the drawing Boy with Big Boots for £22,500 ($35,700) at a Bonhams auction, the buyer sent it to be cleaned, only to discover a valuable signed oil painting on the reverse side of the picture. He then approached art consultant Iain Clark and restoration expert Brian McLaughlin of the Painting & Restoration Studio, who believe the hidden depiction of a young boy to be a painting of one of Eardley’s favorite models, Andrew Samson.

Clark described the moment of realization to be “like the moment in Willy Wonka when they discover the golden ticket.” The anonymous art collector intends to keep both 1950s works for his private collection.