The pop star siblings moved in to a new property together last week (ends01Apr16) after both suffered heartbreak last year (15), with Nick splitting from beauty queen OIivia Culpo and Joe's relationship with model Gigi Hadid coming to an end.
However, with Nick in the U.K. this week (beg04Apr16) promoting his new album, Last Year Was Complicated, he has had to insist his brother doesn't allow friends into his room.
"He is there (their new home) now," he tells the BBC. "I'm like, 'Please don't let other people go to my room when I'm away. Not that there's anything in there that I don't want them to see... That's your space, I think. I trust Joe fully, he won't do that."
Despite having to lay down a few ground rules for his brother and former Jonas Brothers bandmate, the musician is delighted to have his brother living with him again.
"I don't regret it at all, I'm really excited about it but it's definitely so different to see the difference in our personalities and social scene," he says.
Joe's sociable nature even cheered his brother up after he spent the first few nights in the apartment alone, saying, "I was there for three or four nights just getting everything set up and then Joe came in just, like, on fire. It suddenly became a very social environment - the house - whereas before it was just me and my guitar and books."
The siblings are unlikely to spend too long together in their new lodgings however, as later this summer (16) Nick is set to head off on tour around North America, while Joe's band DNCE are booked to play two nights at Britain's V Festival in August (16).
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