Artist Paul Emsley spent several months painting the oil on canvas portrait. It shows the 31-year-old royal against a dark background with her lips pursed into a wry smile.
The Duke and Duchess of Cambridge were on hand to take their first look at the piece on Friday morning. Both praised the painting. Kate told Emsley it was "just amazing." Her husband liked it too, calling it "absolutely beautiful."
But at least one British art critic is calling it a rotten portrait, saying it looks nothing like her.
(The Associated Press contributed to this story)