Britain's Royal Collection Trust has gone Pop Art with the purchase of four famous Andy Warhol portraits of Queen Elizabeth II.

The colorful screenprints are based on a formal photograph of the queen wearing a tiara and necklace that was used during her Silver Jubilee celebrations in 1977.

They will form part of the Portraits of a Monarch exhibit starting in November at Windsor Castle. The purchase was announced Monday, but royal officials refused to say how much was paid for the portraits...