Page Six tells how Frederico Castelluccio, who played Furio on The Sopranos, discovered a significant Old Master painting:

Castelluccio, a painter and expert in Baroque European art, found the work at a Frankfurt dealer, but no one knew who the artist was. It was mistakenly marked as an “18th-century Italian holy painting of Saint Sebastian,” the actor told us. “They had no idea who painted this.”

After winning the work at auction, he had it authenticated by experts, who concluded it was a Guercino, circa 1632-34, by using “infrared reflectography,” X-rays and chemical testing of the pigment.

He then also took years to restore it

‘Sopranos’ star discovers artwork worth millions (Page Six)