World No 2 Dustin Johnson will join a glittering field at next year's JP McManus Pro-Am at Adare Manor.
Organisers have also confirmed that Graeme McDowell, Matt Kuchar, and European Ryder Cup star Rafa Cabrera-Bello will take part.
They come into a field which already includes Tiger Woods, Rory McIlroy, Phil Mickelson, Justin Rose as well as Hollywood stars Mark Wahlberg, Hugh Grant and Jamie Dornan.
Sergio Garcia, Henrik Stenson, Paul Casey and newly crowned Irish Open champion Jon Rahm had already been nailed in for the tournament.
The event takes place on 6 and 7 July in 2020, and will be for the benefit of charities in the mid west.