Koepka is the latest in a long list of players to join a star-studded line-up featuring the likes of Tiger Woods, Rory McIlroy, Phil Mickelson, Dustin Johnson, Justin Rose and Graeme McDowell.
"It's fantastic for the Pro-Am that Brooks has committed to the event and I extend our sincere thanks to him for doing so," said JP McManus. "The event promises to be very special for the spectators to see a player of his calibre in action this July and we are also extremely fortunate to have eight of the world's top ten golfers confirmed to participate."
The Pro-Am takes place July 2020 at the Tom Fazio redesigned golf course at Adare Manor. Mid-west charities will benefit from the Pro-Am, with millions raised since the first event in 1990.