American Thomas uttered the anti-gay slur on the fourth hole of his third round in Hawaii after missing a five-foot par putt, and it caused an immediate stir on social media.

“It’s inexcusable,” Thomas said. “First off, I just apologise. I’m an adult. I’m a grown man, there’s absolutely no reason for me to say anything like that. It’s terrible. I’m extremely embarrassed.

“It’s not who I am, it’s not the kind of person that I am or anything that I do.

“Unfortunately, I did it and I have to own up to it and I’m very apologetic.”

The US PGA Tour is expected to fine Thomas for the remark. “As he expressed after his round, we agree that Justin’s comment was unacceptable,” the PGA Tour said in a statement.

Thomas finished his round by shooting a five-under 68 and is tied for fifth place with one round to play, four shots back of co-leaders Harris English and Ryan Palmer who are at 21-under par.