Flag, by U.S. artist Jasper Johns, is one of four pieces from the collection of the late Michael Crichton set for auction in New York on May 11. (Lefteris Pitarakis/Associated Press)

One of Jasper Johns's iconic Flag paintings, from the collection of the late author Michael Crichton, is being put on the auction block.

The author of Jurassic Park, who died of cancer in 2008 at the age of 66, was an avid art collector.

Four pieces from the writer's collection, valued at £20 million ($33.4 million Cdn), went on display Friday at Christie's in London before they will be auctioned at Christie's in New York City on May 11.

Crichton, one of the most successful writers of his time and also the creator behind the TV series ER, was a knowledgeable art aficionado.

"I just bought images that I enjoyed looking at," Crichton once said about his collecting habit.

He bought Flag, one of a series made by Johns from 1960 to 1966, directly from the artist in 1974.

"It's truly the first great pop art object," said Brett Gorvy, deputy chairman of Christie's Americas. "It allowed artists like Andy Warhol and Roy Lichtenstein to look to the world around them."

Crichton became such an authority on the work of Johns that the artist asked him to write the catalogue for a retrospective of his work in 1977.

Other works from the collection on the block include Picasso's Women and Children from 1961 and pieces by Lichtenstein and Robert Rauschenberg.

Trained as a physician, Crichton was author of The Andromeda Strain, Disclosure and The Lost World. He also directed movies, including Coma, The Great Train Robbery and Runaway.

With files from The Associated Press