What is the name of the stage play co-written by J.K. Rowling that follows Harry Potter as an adult?

The stage play co-written by J.K. Rowling that follows Harry Potter as an adult is Harry Potter and the Cursed Child.

The play is set nineteen years after the events of Harry Potter and the Deathly Hallows. Its central characters include the adult Harry, now employed at the Ministry of Magic, and his son Albus Severus Potter. The story explores their difficult relationship and the consequences of attempts to alter the past.

Harry Potter and the Cursed Child was written by Jack Thorne, based on an original story by Thorne, John Tiffany, and J.K. Rowling. It was directed by Tiffany and first performed in London’s West End in 2016.

Although it continues the fictional timeline, it is a play rather than an eighth Harry Potter novel. The published script was marketed as a special rehearsal edition before a later definitive edition appeared.