The 'Best Song Ever' singer's mum Johanna and her partner Daniel Deakin have become parents to a baby boy and a baby girl, born at Barnsley Hospital in South Yorkshire.
A rep for Louis confirmed the happy baby news to The Mirror, revealing the new arrivals had been named Ernest Rupert Atholl Deakin and Doris Poppet Deakin.
"All the family are delighted," they added.
So far, Louis, 22, has not made any reference to the babies on his Twitter account, although his grandfather Keith hinted at the arrivals by tweeting: "Today is a good news day :)."
It's gearing up to be a big month for Louis. Not only has he new baby siblings, he's also preparing to make his debut for Doncaster Rovers' reserve side.
The lifelong Rovers fan joined them on a non-contract basis last year but a planned debut in September 2013 fell through because of injury. It's now been set for 26 February, a match in aid of Bluebell Wood Children's Hospice.
Louis can expect to play to a sold out crowd as the club recently said fans from as far afield as France, Italy and Sweden had requested tickets.
Meanwhile, the One Direction boys are currently on a brief hiatus following a hectic year of touring and the release of their debut movie, but they'll be back together again later this year for their mammoth stadium tour, which kicks off in Ireland in May.
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