And while the Doncaster lad isn't thrilled at the prospect (he tweeted last week: "22 is old"), here at HuffPost UK, we feel we need to celebrate. So what better way to mark the occasion than with Louis' 22 funniest pictures?
Happy birthday Loulou, you little bum-fluff-chinned sass-pot.
The other members of One Direction thought the sun shone out of Louis' backside. They were wrong.
But Louis assures us everything is still in good working order down there.
Still, no need to brag though, Lou.
Did you know that Louis is the owner of an invisible pet horse?
... and once fell victim to the ultimate soft toy photobomb.
Louis couldn't hide his excitement as The Wanted took to the stage.
Ooops, that will teach us to make jokes about Louis liking The Wanted.
Louis just couldn't get enough of Liam's dad jokes...
... especially when they were about playing with his super soaker *sniggers*.
Louis couldn't hold on until he got home.
"Oh Liam stop, you say all the sweetest things."
Louis was shocked to see the things Harry had been texting his new girlfriend.
When Louis asked if we wanted something from the trolley, this wasn't exactly what we had in mind.
Louis proving he's sassy even when playing football.
And he couldn't help but snigger when Harry complimented him on his ball skills.
One for all the Larry Stylinson fans out there.
"Do you think I'd look good with a 'tashe?"
Louis was overjoyed to be replacing Brucie on 'Strictly'
Louis couldn't get through a whole rendition of One Direction's biggest hit, 'What Makes Spew Beautiful'.
Louis didn't seem to mind when the 'X Factor' wardrobe team mixed his clothes up with Diva Fever's.
When Louis forgot to put his contacts in one morning, he had trouble recognising girlfriend Eleanor Calder.
Louis Tomlinson - owner of the sassiest fringe in showbiz.
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