Celebrating his 90th birthday on May 31, American artist Ellsworth Kelly is experiencing widespread attention this year through a number of exhibitions at museums and galleries across the globe.

Known for his use of simple forms and bright colors, Kelly (b. 1923) is associated with some of America's most recognizable 20th-century art movements, among them, hard-edge painting, Color Field painting and the minimalist school.

The still active nonagenerian is a sculptor, printmaker and painter who worked as a camouflage artist for his army battalion during World War II; later, he used the G.I. Bill to train at the School of the Museum of Fine Arts, Boston.

The artist's dealer, Matthew Marks Gallery, is showing "Ellsworth Kelly At Ninety" at its New York location through June 29.

Works on paper are the focus of an exhibiton at the National Gallery of Art, the Philadelphia Museum of Art is showing four works that span the artist's career, and the Phillips Collection will exhibit recent panel paintings, beginning June 22. More shows are set to open at the Pompidou Center in Paris, the Tate Modern in London, the San Francisco Museum of Modern Art, and the Art Institute of Chicago.

Philadelphia's Barnes Foundation, ensconced in its new building downtown, has even got a gallery devoted to Kelly in what the museum calls its "first show of contemporary art in 90 years." “Ellsworth Kelly: Sculpture on the Wall,” which opened on May 4, is centered around one large-scale and powerful work: the 1956-57 “Sculpture for a Large Wall,” comprised of 104 anodized aluminum panels, some undulating in shades of red, blue, yellow and black, and measuring 65 feet long.

The work was Kelly's first public commission, made for the lobby of the Philadelphia Transportation Building. It was lost for a while before working its way to the Museum of Modern Art (MoMA).

MoMA is holding its own Kelly exhibition, focused on his Chatham Series, the first works the artist completed after leaving New York City for upstate in 1970.

For the first time in 40 years, all 14 of the Chatham Series paintings will be reunited. Each is comprised of two canvases that form an inverted L shape, creating a two-color, minimalist effect. Not far off from his days as an army camouflage artist, Kelly's aim was to create art that felt "anonymous" by erasing all traces of the artist's hand.