"One Direction was never Zayn's sort of music so he always wanted to find something else," Payne, 21, said Monday during an interview with Nick Grimshaw on BBC's Radio 1. "If your heart's not into something you can't just carry on doing it because of fame and stuff. You have to go and do what you want to do."
Payne complimented Malik, 22, on his new record deal with RCA, saying he is "off doing his own thing at the moment, which is cool for him."
There appears to be no bad blood between Malik and his former bandmates, despite a previous Twitter skirmish. On Saturday, Malik said that the band's new single, "Drag Me Down," is "sick" and that he was "proud" of the band.
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Payne also chimed in on Louis Tomlinson's forthcoming fatherhood in a different radio interview on Monday, this time with Magic FM's Jo Parkerson.
"Well, I was quite obviously a bit shocked, but he's taken super well to it," he said. "He's very excited about what's going on with him at the moment."
Payne added, "Sometimes stuff happens like that … and not [as though] it's a small deal ... You know, he's taking it very seriously. It's all good."
The singer also said that Briana Jungwirth, the soon-to-be mother, is a "lovely girl," although the idea of having a baby roaming around soon is "quite a crazy thought."