Simpson ended his two-year romance with the model earlier this year (15) and she has recently been spotted with best pal Taylor Swift's ex-boyfriend.
Although both have played coy about the love story, Jonas' little brother Nick has confirmed they're a couple, telling E! News he thinks they make a lovely couple.
The Jealous singer says, "I like them together. It's a good thing.
"Joe and I are best friends. We're each other's support system and closest friends, so naturally I'm gonna see a lot of her because they're together and it's great. I'm really happy for them. I think they seem very happy together and it's good."
And Simpson, who recently confessed he'll always love Hadid, has nothing but cool thoughts about the new couple.
He says, "It's all cool. We have all mutual friends and stuff in New York. I'm cool about it.
"I'm sort of impartial to the whole thing and I try to remain nice to everyone and not cause any bad blood or anything."