The pair teamed up with Nicki Minaj for the hit track Bang Bang, and during that time Jessie got to know the young American singer.
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Jessie J has spoken out in defence of Ariana Grande
"I always say, judge a person when you meet them," Jessie told US Weekly when asked about recent reports that Ariana is difficult to work with.
"I've met Ariana, and there's a very thin line between 'diva' and 'survival'. And a lot of people can't (differentiate that) – and I've had that," she said.
"I've had the diva stuff. And it's when people can't cope with how passionate you are, and how much you care.
"She's super talented, she's very young, and she's very sure of what she wants," the Domino singer added. "I think she's wonderful. She's great."
Jessie J on Ariana Grande: "There's a very thin line between diva and survival"
Jessie's comments echoed those she made in a previous interview with the Huffington Post, in which she said she saw herself in Ariana at that age.
"One thing that I really observed with Ariana is how impressed I was with her age and her work ethic," the 26-year-old said. "She really cares. And she sings constantly. I love that because that's how I saw myself when I was her age – that the vocals were the most important thing.
"I admire that. So I really, really learned from her. I was like, 'I need to be consistent. Come on, you can do this.'"