A painting by Francis Bacon is expected to break the record for the artist's work when it is auctioned in May.
Bacon created more than 50 portraits of Catholic church leaders
Study from Innocent X could fetch more than $30m (£15m) when it goes under the hammer in New York, Sotheby's said.
The painting, from Bacon's Popes series, has been in the same private collection for more than 30 years and has never been sold at auction before.
Another Bacon portrait - The Study for Portrait II - sold for a record £14m at an auction in London in February.
Study from Innocent X will go on view to the public in the UK at Sotheby's New Bond Street galleries in London from 18 to 20 April.
The painting, which was completed in 1962, was described as the "ultimate Pope image" by Tobias Meyer, worldwide head of contemporary art at Sotheby's.
"It is intense, luminescent and radiant. His painterly skill is extraordinary and the canvas possesses a Baroque energy," he said.
The painting will be sold on 15 May as part of Sotheby's contemporary art sale, which also includes Mark Rothko's White Center (Yellow, Pink and Lavender on Rose), expected to fetch more than $40m (£20.3m).
Bacon was born in Ireland to English parents, but he left Ireland when he was a teenager. He died in Spain in 1992.
His Popes series was inspired by Diego Velazquez's 1650 Portrait of Pope Innocent X.