Martin Kaymer and Luke Donald added to strong Irish Open field

Martin Kaymer clinched a hugely impressive eight-shot win at last year's US Open at Pinehurst

US Open champion Martin Kaymer and former world number one Luke Donald are the latest big names to confirm entries for next month's Irish Open.

Kaymer and Donald will join a Royal County Down field which includes Rickie Fowler, Sergio Garcia, Ernie Els and world number one Rory McIlroy.

McIlroy's charitable foundation is hosting the 28-31 May event and he has coaxed a host of top stars to compete.

American Patrick Reed and England's Lee Westwood will also participate.

In addition, the field will include major winners Graeme McDowell, Darren Clarke and Padraig Harrington.

The prize fund for the European Tour event has also increased by 25% with this year's purse just under £1.8m.

Els revealed that he agreed to compete at Royal County Down in the hope of convincing McIlroy to play in next year's South African Open.

"We kind of struck a little deal myself and Rory," Els told BBC Sport Northern Ireland.

"I'm going to play in his Irish Open this year. It's at (Royal) County Down an unbelievably classic links course.

"I'm hoping to get him to play in our home open, the South African Open. We'll see how that pans out."