The Dubliner brought the American to Powerscourt hotel in Co. Wicklow over the weekend and cosied up to her to pose for a romantic picture in its front lawn.
He also captioned the picture with four love hearts and a smiley face with more cupid symbols.
This is the first time the couple have been pictured in Ireland and comes several months after Barry split from his Kerry girlfriend Shona Guerin.
Barry was pictured earlier this year with Alyson in London, where the 28-year-old has a home in the docklands area of the English capital.
In April Dwayne ‘The Rock’ Johnson posted a video wishing Alyson a happy birthday and referenced Barry in it.
“I wanted to wish you a happy birthday. Our boy Barry left me the most beautiful text and I won’t tell you everything he said in it, but he did say this and I quote, verbatim, ‘She is very special to me’,” Dwayne said on Instagram.
“So, I wanted to pass it on to you. It’s a very true story, he just texted me. Happy birthday! Thanks for being a fan. I heard you were a big fan – that’s awesome, thank you very much. You guys have the best birthday weekend.”
Little is known about mystery woman Alyson yet.
Barry and Shona unfollowed each other on social media last year, sparking rumour they had split.
The actor shared public messages in February saying he was ‘back to good’ before posting a smiley snap with Alyson.
Barry is on a break from filming in the west of Ireland Martin McDonagh’s The Banshees of Inisherin’, which also stars Colin Farrell and Brendan Gleeson.
Last month, the Sunday World’s story about the actor being beaten up in Galway made international headlines.
Barry was found bloodied and bruised near the G hotel in the early hours of August 15 and taken to hospital by ambulance and treated for his wounds.
He is Barry currently preparing for the release of the new Marvel blockbuster, Eternals, in which he stars alongside Angelina Jolie, Salma Hayek and Kit Harington.
Such is the standing of the Dublin-born star, who plays Druig in the movie, that this week he is the cover star on American celebrity publication Entertainment Weekly.
Film industry experts reckon Barry will collect at least €2 million for his role and that he currently has a net worth of about €13 million. Keoghan is also fronting the current TV ‘welcome back to the pubs’ advertising campaign for drinks giant Guinness.
The young Dubliner first sprang to fame in 2013 as the ‘cat killer’ Wayne in RTÉ’s crime series Love/Hate, having started his acting career in 2011 when he saw a casting notice for Irish gangster movie Between the Canals.
Barry grew up in the Summerhill area of north inner-city Dublin, close to where Olympic gold medallist Kellie Harrington hails from. He still visits his inner-city haunts and feels very much at home there, where locals jokingly have nicknamed him ‘Hollywood’.
“All I get is, ‘Alright Hollywood, get us a drink there, would ye?’,” he once said. “That’s all I’m referred to as, ‘Hollywood’. I’ve no first name. But it’s great to have that sense of humility and being brought back down.”
He has also bravely spoken about his mother, who died of a heroin overdose when he was 12 years old. He told Ryan Tubridy on The Late Late Show in 2018 that he and his brother Eric were shuttled between 13 foster homes during their childhood because of her addiction.
“The drugs hit the area and affected all the families. She was one who got caught,” the star said.
“We went into foster care. The families were good to us that we went to, we went to a few of them. As a kid you don’t know what’s happening … you get attached and them – boom – let’s move over here… it’s only when you get older you can look back and get a bit of perspective.”
He was aged just 12 when his mother succumbed to her addiction.
“I have great memories of her. Very proud of her,” he added. During the interview, he also revealed how he one days hopes to win an Oscar.
“I’ll put the Oscar there,” he said, pointing to Tubridy’s desk. “Put the other one there, and the other one there.”
Keoghan is also fronting the current TV ‘welcome back to the pubs’ advertising campaign for drinks giant Guinness.