The pair will reprise their roles from the 2017 Broadway revival of the hit Stephen Sondheim and James Lapine musical.
Sunday in the Park with George will play at the Savoy Theatre in London's West End for a limited season from 11 June to 5 September 2020.
Tickets are on sale now.
With music & lyrics by Sondheim and a book by Lapine, the musical is inspired by Georges Seurat's iconic painting A Sunday Afternoon on the Island of La Grande Jatte.
Gyllenhaal stars as Georges Seurat/George while Ashford plays Dot/Marie.
Gyllenhaal said: "Performing Sunday in the Park with George with the brilliant Annaleigh Ashford was one of the greatest joys of my career, I've also deeply missed the West End and so to be bringing Stephen Sondheim and James Lapine's Pulitzer Prize-winning musical there alongside Annaleigh is both humbling and thrilling."
Ashford added: “Sharing the masterpiece that is Sunday in the Park with George with audiences, has been one of the greatest pleasures of my artistic life. It is an honour to play Dot again with genius Jake Gyllenhaal and to tell this story of children and art to the great city of London.”
James Lapine & Stephen Sondheim said “We are thrilled that a London audience will get to see the recent Broadway production of Sunday in the Park with George with Jake Gyllenhaal and Annaleigh Ashford reprising their extraordinary performances.
"We also look forward to seeing them joined by a terrific British company.”
Further casting is to be announced in due course.