Ryan Tubridy posted a picture with the "very lovely" future royal on Instagram and told his listeners on RTÉ Radio One that she was "good fun" and "elegant", but that despite reports, the pair are "not friends'".
Taking the opportunity to clear up some recent press reports, The Late Late Show host explained: "I mentioned this a few months ago and it seemed to get into the ether that she was my old friend Meghan Markle...and people thought I was seriously her friend. I met her for seconds.
"I've been getting calls from the UK since she got engaged to Prince Harry asking me to take part in documentaries and I had to explain that I met her for seconds.
"There has been a terrible mistake and I was joking!"
Tubs also explained how the selfie actually came about: "At the White House Shamrock Ceremony that I was invited to – which I loved – I was introduced to Meghan Markle as an actress in the TV show Suits. She was having coffee with a friend of mine.
"She was very very lovely and elegant and good fun. She was a very pleasant person to meet. I met her for about ten minutes in total. We walked from the W Hotel across the road to the White House and I said sure we might as well do a selfie for the craic."
He added: "I think he (Prince Harry) is a lucky man and I hope that all works out."