Charl Schwartzel, Bubba Watson, Dustin Johnson and John Daly have confirmed their intention to play at next month's RBC Canadian Open at Glen Abbey Golf Club in Oakville, Ont.

They join a field that already includes Matt Kuchar, Luke Donald, Ernie Els, Hunter Mahan, Jim Furyk, Mike Weir of Bright's Grove, Ont., and defending champion Scott Piercy.

"I haven't been to the RBC Canadian Open since 2008 but I'm really looking forward to playing again this year," Johnson said Thursday in a release.

"The field is looking strong and Canadian golf fans have always been very supportive of me. I'm feeling really good about how my game is rounding into form and am excited to play Glen Abbey in a few weeks."

The 104th edition of Canada's national open golf championship will be played July 25-28.