A masterpiece has been hiding in plain sight since 1999.

While watching the 1999 children’s film “Stuart Little,” which starred Geena Davis, Hugh Laurie, Jonathan Lipnicki and a talking mouse voiced by Michael J. Fox, a viewer spotted a Robert Bereny masterpiece in the background, according to ABC News. Bereny was an early 20th century painter from Hungary.

The Bereny painting, titled “Sleeping Lady with Black Vase,” was a long-missing piece. The painting appeared in scenes of “Stuart Little” involving the stars of the film, yet it wasn’t until 2009 that the painting was identified.

The eagle-eyed viewer, who is also an art historian, notified people associated with the Columbia Pictures film and the painting was tracked down. An assistant set designer had purchased the artwork for $500 as a prop for the film, and it was later sold to a private collector. Now the painting is up for auction, with a reported starting price of around $138,000.

Watch the ABC News segment below: