CHULA VISTA, Calif. – Fans headed to Thomas Rhett’s Saturday evening concert in San Diego County were shocked when the country singer announced that the show was canceled less than two hours before he was expected to hit the stage.

The “Life Changes” singer took to Twitter around 5:30 p.m. Saturday to tell fans that due to health issues, the concert- scheduled to start at 7:30 p.m.- would no longer go on.

“Hey San Diego, it breaks my heart to say this but unfortunately I am not able to sing tonight due to vocal irritation and swelling and we are having to cancel the show at North Island Credit Union Amphitheatre,” Rhett wrote.

Concertgoers were quick to point out that some fans were already at the venue while others were waiting outside, sitting in traffic, and on their way to the event.

Rhett explained that he and his team were working throughout the day to help him recover, but that their efforts were unsuccessful and that he was advised to rest his voice.

“I am so sorry this announcement is so close to show time. For those of you who have already traveled to the show I sincerely apologize. We’ve been working all day to try and make the show happen, but it’s just not going to be possible and have been advised not to perform this evening,” Rhett said Saturday.

Despite backlash, many fans seemed to understand and replied to his tweet, wishing him a speedy recovery and a return to San Diego soon.

Anyone who purchased a ticket will receive a refund, according to the singer.