ONE is a new dad, juggling nappies and night feeds, the other is a global superstar and one fifth of the biggest boy band in the world.
Their lives are worlds apart, but One Direction singer Niall Horan and his big brother Greg are as close as ever.
Last week, Niall flew Greg, his wife Denise and the couple's newborn son Theo to London to see the world premiere of One Direction's 3-D concert film extravaganza This Is Us.
The film charts the meteoric rise of the boy band, who have achieved worldwide fame and success plus legions of adoring fans since forming on The X Factor in 2010.
Niall's mother Maura, father Bobby and their respective partners as well as two friends of the singer also attended the premiere.
Greg, 26, who is prouder than anyone of his famous sibling, works in the Spar store in Mullingar and insists he would not have it any other way.
He told the Sunday Independent: "Four years ago he was nobody. He was a young lad from Mullingar and now he's in the world's biggest boy band, travelling to the second premiere in a week. It's amazing."
In May, Greg married his partner, Denise Kelly, in St Michael's Church in Castletown, Co Westmeath, with Niall by his side as best man. The wedding featured in This Is Us.
"It was amazing to see my own wedding on the big screen," said Greg.
"It was, 'Wow – I'm a big movie star now!"
Greg admitted the family were struggling to come to terms with the sheer scale of Niall's success.
"We're all baffled, and we're all overwhelmed," he said. "He's proud of what he's achieved and by how far he's come, and so are we.
"We miss him too. It's hard, but we know what he does and we're proud of him for what he does. We have a look at Twitter and see what he's up to."
Meanwhile, thousands of miles away in New York, Niall and his One Direction bandmates are taking over the US.
Former Spice Girl Mel B – currently a judge on America's Got Talent – was also a guest on the show, but she walked around easily and mostly unnoticed in the plaza, not being stopped once for an autograph or a photo.
The boy band exited through an underground car park in a fleet of blacked-out SUVs on to Sixth Avenue. Regular security staff at the Rockefeller Plaza joked, saying: "You'd think it had been the Obamas that was here with all that drama."
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More than 20,000 fanatical One Direction fans, many of whom had slept out on the streets of Manhattan for six nights, turned out to see their idols.
Justin Bieber recently played there, but the hysteria did not reach such fever pitch for him.
Bemused security personnel at the Rockefeller Plaza told the Sunday Independent they had never witnessed such "mania for a band", with young female fans fainting and office workers' children hanging out of the windows of nearby skyscrapers.
One well-known member of the American paparazzi who takes pictures of celebrities every day and works at pop concerts stated that "Bieber is dead" on seeing the hysterical atmosphere as thousands of fans waited to see One Direction.
Amid ultra-tight security that included members of the NYPD and several bodyguards for each band member, we came face to face with Niall as he was whisked from the stage to the exclusive green room area.
In a sky-high, jovial mood, he stopped briefly to speak to the Sunday Independent.
Asked for a message for his fans at home, the now world-famous pop star gave a high-five and shouted: "How are ya, Ireland!"
Niall, who'll be 20 next month, was then quickly ushered on by his bodyguards, two in front of him and two behind, as he walked back into the glare of the celebrity spotlight, a world away from the his family home and the life he left behind in the heart of the Irish midlands.