Question: why has Mullingar man Niall Horan ended up on a list of Britain's richest young stars?

Niall Horan has many millions of fans - and they likely all know that the singer is a proud Irishman. 

However, the music star has been named as one of the top 30 richest stars under the age of 30 in the UK. The County Westmeath-native was listed as having a staggering fortune of $59m (€52m).

On the list of budding multi-millionaires, Horan was joined by his one-time One Direction bandmates. Harry Styles made the list in fourth place, with an estimated net worth of $73m (€65m). Louis Tomlinson, Liam Payne, and Zayn Malik all made the list too.

Read more: Could One Direction millionaire Niall Horan lose it all?

I’m raffling off the shirt I wore at last year’s Jingle Bell Ball to celebrate @raysofsunshine’s 15th Birthday ! I love being an ambassador for this charity and hope you’ll support them by buying a raffle ticket . Enter here: https://t.co/SAKo74IdeI 🎉 #15YearsOfSunshine pic.twitter.com/RDxqtqn4qV

— Niall Horan (@NiallOfficial) October 19, 2018

The annual list, compiled by Heat Magazine, notes that 25-year-old Horan made his fortune through both his stint in the global chart-topping boyband and his solo career.

"Since cutting ties with Simon Cowell, Niall has signed a £4m ($5m) record deal, had a US #1 album, while he's predicted to make €10m ($11m) from his 81-date world tour. Owns a glass-fronted London apartment which comes with its own penthouse cocktail bar. And why not? He can afford it."

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Camden NJ 📸 @christiantierney

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As for why he is included as the sole Irish person amongst Britons? Well, they do have a habit of 'claiming' successful Irish talent as their own when it suits!

Singer Adele ranked first with an estimated worth of $201m as the richest, young British star. Ed Sheeran followed in close second, with $122m 'in the bank.'

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WATCH: Humble Niall Horan nails performance with top Irish orchestra

Niall Horan attends the Horan And Rose Charity Event held at The Grove on June 23, 2018, in Watford, England. NEIL P. MOCKFORD/GETTY IMAGES