Donald Trump has listed his Doonbeg hotel as one of the properties he owns in the UK.
The US President was answering questions about a post-Brexit trade deal at the end of the G7 summit in Biarritz, France when he made the slip up.
The billionaire dismissed claims he wold "do over" the UK in a future trade deal.
Trump insisted he "loves the UK", before boasting about the properties in owns in Britain - and citing his Co Clare resort.
He said: "No, no, no. I love the UK. I own property in the UK. I love the UK.
“I have no idea how my property is doing because I don’t care, but I own Turnberry [in Scotland] and I own in Aberdeen and I own in Ireland as you know – Doonbeg – great stuff.”
The POTUS visited the hotel in June on an unofficial visit after landing in Shannon Airport.
His comments caused outrage on social media and have been blasted as "insulting".
One person said: "Ireland is NOT part of England. Ireland gained its independence in 1919.
"Learn some history before you open your mouth and spout your ignorance regarding Ireland's hard earned autonomy."
A second Twitter user added: "Are you really so stupid as to think Doonbeg Ireland is in the UK?
"Don’t you realize how insulting it is to Irish-American voters for you to say this?"
A third said: "Doonbeg, Co Clare is in the REPUBLIC of IRELAND! History lesson, we won our Independence in 1919! How insulting."
Meanwhile, Trump warned Boris Johnson he would struggle to strike a new Brexit deal with Brussels – heightening fears the UK will leave without a pact.
Forging a fresh agreement with the EU would be “tough”, the US President said, as he hailed European negotiators.
He delivered the doomsday alert after lavishing praise on the rookie Prime Minister following three days of talks at the G7 summit in Biarritz.
Speaking at a press conference in the French seaside resort, Mr Trump said: "Boris has to try and do something with Brexit - it's very tough.
"I deal with the EU - it's a very strong group of people, they have their ideas and they're not easy to deal with, I will tell you.
"The EU is very tough to make deals with - just ask Theresa May."
The latest siren warning came as the PM desperately tries to renegotiate the Withdrawal Agreement, vowing to strip the Irish Backstop – designed to prevent a hard border between Northern Ireland and the Republic – from the pact.
The PM and President beamed over the weekend as they held their first face-to-face talks since Mr Johnson entered No10.
