Rolling Stone magazine reports McGraw collapsed while performing Sunday night in Dublin.
McGraw's wife, singer Faith Hill, can be seen in a video on a fan's Instagram page saying, "He's been super dehydrated. I apologize, but I made the decision that he cannot come back out on stage."
A representative for McGraw issued a statement saying McGraw was attended to by local medical staff on-site and will be fine.
McGraw, who was performing as part of the Country to Country festival in the U.K., had performed Friday night in London and Saturday night in Glasgow as part of C2C, a three-day, three-city country-music festival.
The duo is scheduled to begin their 29-city Soul2Soul tour in the U.S. on May 31 in Richmond, Virginia.
