She even dated his brother Joe after meeting him on the set of 2008's Camp Rock – but, and a full six years after that particular romance ended, Demi Lovato and Nick Jonas remain famously close.
Indeed, it seems that the 23-year-old super-star singer and actress has PLENTY to say about her BFF's love-life.
Step forward Olivia Culpo: a 24-year-old one-time Miss Universe and model. She and Nick dated for two years, but sadly split in May.
And Demi reckons Mr Jonas is well rid.
"Honestly, I didn't like her anyway," she's just told Billboard magazine.
"It's not because she's mean or anything, but he has such a great sense of humour and I want him to be with someone that makes him laugh."
Ouch.
That's not all – Demi hints that Olivia and Nick, 23, were an ill-suited match from the outset.
"He's a guy in his twenties and he's famous and he likes to have a lot of fun," she furthermore told the magazine – most probably referring to Olivia (although she doesn't name her).
"Listen, even when he was in a relationship, I was like, 'Get out of that. You could f*** anybody that you want right now, so have fun and do that," she added.
Fair play, Demi.
Nick and Ms Lovato are about to embark on a world-tour together and have been promoting their concerts – with Nick also chatting to the same publication in a joint-interview which includes plenty of racy shots of the pair.
At least Nick himself could pipe-in with a few thoughts of his own relating to Demi's love-life.
"For a couple of years there was the Joe and Demi romantic thing, so I’d be this emotional bridge for them," Nick revealed.
Demi is currently single after splitting from actor Wilmer Valderrama earlier this year following six years together.