Biden says 'I may be Irish but I'm not stupid' - then confuses Jill's father with her grandfather

It is one of President Joe Biden's favorite lines, allowing him to riff on his Irish heritage and his love for Jill Biden.

'I may be Irish but I'm not stupid,' he told an audience in New Castle, Delaware on Friday, before delivering the punchline: 'I married Dominic Giacoppa's daughter.'

The line got a laugh — as it did on St Patrick's Day at the White House.

Just one problem. It is not accurate.

Biden actually married Dominic Giacoppa's granddaughter, as factcheckers point out each time the joke is deployed.

'I may be Irish but I'm not stupid,' President Joe Biden said on Friday. 'I married Dominic Giacoppa's daughter.' In fact he married Donald Carl Jacob's (pictured) daughter, the granddaughter of Dominic Giacoppa. The line got a hearty laugh anyway

The Bidens pictured in 1977, shortly before their wedding. She is the granddaughter of Giacoppa who arrived in the U.S. from Sicily and soon changed his family name

Giacoppa emigrated to the U.S. from Sicily. Not only was his family name actually Giacoppo (misspelled as Giacoppa at Ellis Island), but he soon changed it to something that Americans would find easier to pronounce.

And so it was that Jill's father was called Donald Jacobs.

Biden has got it right in previous years. 

In 2013, at the Italian ambassador's "opera ball" he told guests: 'Every year is the year of the Italian in my house

'I'm always referred to as an Irish politician — but I was smart enough to marry Dominic Giacoppa's granddaughter.'

This time around, he delivered the line during a speech to encourage military veterans to take advantage of new healthcare opportunities under legislation that he signed in August.

The event was held at the Major Joseph R. 'Beau' Biden III National Guard/Reserve Center, which was named after his son who died in 2015 of brain cancer. 

Biden spoke on Friday at the  Major Joseph R. 'Beau' Biden III National Guard/Reserve Center, which was named after his son who died in 2015 of brain cancer

'I drive by this building a lot for Air Force One, to fly back and forth to Washington, and I always get a lump in my throat,' Biden said. 

'Y'all know what a burn pit is? It's a hole between eight and 10 feet - high as 12 feet deep. The size of a football field, great big rectangle. And every damn ugly thing in the world was burned. Everything. Everything. Toxic waste, everything,' Biden said. 

'I'm no doctor but it's pretty clear a lot of guys and women getting sick,' he added. 'It's not unique to me and my family.'

 He said he was determined to take action.

'Come hell or high water,' Biden said. 'I made it real clear to the United States Congress if they didn't pass this damn burn pit bill, I was gonna go on holy war, not a joke.' 

Biden then revealed that his uncle Frank Biden fought in the Battle of the Bulge and won the Purple Heart but never received it. Joe Biden, when he became president, got his uncle's Purple Heart and presented it to him at home. 

Biden is pictured with 102-year-old World War II veteran Ray 

Biden said his uncle told him, 'I don't want the damn thing,' adding 'the others died. I lived.' 

The Battle of the Bulge was the Adolf Hitler's last major offensive in World War II in Belgium. It was the deadliest battle ever for the U.S. Army, which suffered 100,000 casualties. 

Biden then paid tribute to a 102-year-old veteran who he said flew 25 missions over Germany. 

'First lieutenant, young guy, 102 years old, Ray,' Biden said. 'My claim to fame is I used to be his county councilman!'

Biden signed the burn pits legislation, the PACT Act, in August. It passed the Senate on an 86-11 vote after back-and-forth over GOP concerns about its funding. 

The bill removed the burden of proof from veterans who suffer from a litany of illnesses from asthma to terminal cancers after being exposed to toxins in Iraq and Afghanistan.