Taoiseach Leo Varadkar said he has spoken to his partner Matt Barrett about comments posted on social media before and during the coronation of King Charles.
Mr Vardakar said the posts to a private Instagram account were never intended to become public but added it will not happen again.
In a post on Twitter, Mr Barrett said: "On reflection, poor judgment on my part. Unreservedly apologise for any offence caused."
Coronation attendees had been asked to turn off their mobile phones. However, Mr Barrett posted comments and photographs from within Westminster Abbey.
“Holy s*** I think I’m accidentally crowned king of England,” he posted from the Taoiseach’s car as they approached the abbey on May 6.
Mr Barrett, when inside the abbey, continued to post messages to the account despite those attending being asked to switch off their phones.
He posted a picture of part of the order of service, circling in green the last line: “The queen’s sceptre and rod are brought from the altar by the Right Rev and Right Hon the Lord Chartres GCVO and the Right Rev Rose Hudson Wilkin CD MBE, Bishop of Dover. The queen touches them in turn,” it said.
Mr Barrett wrote: “Sounds like the script to a good night out, tbh."
He also posted a photograph of Charles wearing his crown, comparing it to the sorting hat in the Harry Potter books. “Was genuinely half expecting it to shout ‘GRYFFINDOR,’” he wrote.
Asked if his partner should apologise. Mr Varadkar said he is "a private individual".
"They were private messages sent on his private account, he never intended them to go public, but that happens sometimes," Mr Varadkar said. "We've spoken about it and it won't happen again."
