The US President is backing the Irish Rugby team to win the Six Nations.
Joe Biden was speaking during St Patrick's Day celebrations in Washington DC.
Taoiseach Leo Varadkar told President Biden to expect a big welcome when he arrives in Ireland next month.
"I’m really looking forward to your visit," Mr Varadkar said on Friday.
“I promise you that we’re going to roll out the red carpet and it is going to be a visit like no other.
“Everyone is excited about it already. We’re going to have great crowds that would love to see you," he added.
Ireland play England at the Aviva Stadium on Saturday with the Grand Slam on the line.
Kick-off is at 5pm.
Speaking at the White House, President Biden welcomed his relative and former Ireland player Rob Kearney.
"We've even got a few of my distant Irish cousins here today - including the well-known Irish rugby player Rob Kearney," he said.
He then asked Mr Kearney to stand up, telling him: "Rob, I expect we know, and this is no offence to anyone, but we know who we're rooting for in the Grand Slam match between Ireland and England".
President Biden paid tribute to the relationship between Ireland and the US.
"That's what friendship between Ireland and the United States is all about: we rise together in our joys and our triumphs, we persevere together in our sorrows and our setbacks, and we dream together over horizons we can't even see.
"We build together a future that may be... and in these rooms we see the dreams of one Irish builder made real," he added.
President Biden also told singer Niall Horan he is welcome back at the White House anytime.
The former One Direction star performed there, singing four songs - including two on the theme of emigration.
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Reporting by Sean Defoe in Washington DC