The host of his self-titled BBC Radio Ulster show says he is "mortified" after rolling in half an hour late yesterday morning.
Stephen Nolan told the Belfast Telegraph of the “horrible feeling” when he realised he had overslept.
His loyal listeners were left baffled after tuning in at 9am to music instead of Nolan’s usual enthusiastic welcome.
When he finally hit the airwaves 25 minutes later he said he was “scundered” that he had slept in until 8.30am.
He blamed his slow start on a new fitness regime involving intensive work-outs and a new diet plan in preparation for a six-mile challenge for Sport Relief.
“I'm mortified, it was one of those horrible feelings of waking up and realising I definitely didn't have time to get to work,” he told the Belfast Telegraph last night.
“I trained for an hour on Tuesday and haven't recovered yet. It nearly killed me, but I've promised to do six miles for Sport Relief in just eight weeks’ time and that means I have got to push myself very hard.
“I'm looking for listeners to BBC Radio Ulster's Nolan show to do the first mile for Sport Relief with me. I need them to tweet their name to @stephennolan or email me directly at email@example.com."