She might be only 20 but Demi has packed a lot in to her short time on the planet - namely releasing three albums, having gravity defying unicorn hair, becoming an X Factor judge and spending 2 years of her life dancing about with a giant, purple dinosaur.
With those achievements in mind and it being her birthday, we thought we'd take a moment to wish her all the best and find out which celebs have been wishing her many happy returns. Turns out it's mainly just Niall that wanted to get in there though.
That's right - Nialler pipped Demi's old pals Taylor Swift, Selena Gomez and even her new BFF Simon Cowell to the post with his birthday mesage.
"@ddlovato happy birthday honey! Have a lovely day! See ya soon," he tweeted.
Honey? See ya soon? What are we missing here Niall? It sounds like someone has been spending a little too much time in the company of Louis 'honey badger' Tomlinson to us.
In fact, from the very early hour the message popped up on Twitter, it looks like he sent it pretty much as soon as he'd got out of bed and put his socks on.
Presumably if they were in the same country, Niall would have gone even more Luigi T and organised some sort of giant cake to burst out of while doing a sexy dance. Probably to the tune of Barney the Dinosaur.
Isn't that a lovely, if not mildly disturbing, image?