Tim McGraw collapsed onstage Sunday night during a concert in Dublin, Ireland.

The 50-year-old country music superstar had just finished singing "Humble & Kind" when he dropped to his knees and took a seat. McGraw's wife, Faith Hill, later addressed the crowd on his behalf, saying it was her decision to stop his performance. "He's been super dehydrated," Hill told their fans. "I apologize, but I made the decision that he cannot come back out onstage."

In response, the crowd chanted "We love Tim," and Hill performed an a capella rendition of "What a Friend We Have in Jesus." Then the lights came on and the audience was ushered out.

"It was close to the end of the concert. The lights went off and you could see him fall, then he was on his knees," an eyewitness tells E! News. "Shortly after, there was an announcement that there was a medical issue and to be patient. Another 10-15 minutes later, Faith and the band came out altogether and said Tim was very dehydrated. The crowd was chanting, 'Get well, Tim!' She then sang a song and it was all over."

A second eyewitness tells E! News several members of the band and crew rushed onstage to help McGraw get on his feet and take him offstage. "The crowd was really worried, like, 'What just happened?'" Hill "didn't seem that worried or distracted" when she returned to sing a few lines from the gospel song. "And that was it," the eyewitness says. "The concert was cut short."