Harry Styles is apparently "stuck" in the rockstar lifestyle.

The One Direction star is often touted as the edgiest one in the group with his cool sense of style and friendships with the likes of Cara Delevingne and Chris Martin.

While it might seem like he's living the dream, the 21-year-old is thought to be becoming disillusioned by it all.

"It's like he's stuck in the rock'n'roll lifestyle," an insider said to British magazine Star. "It used to be so much fun, but he's beginning to feel unfulfilled. And the exhaustion is starting to show."

It's a tough time for the band, who had to cope with Zayn Malik leaving in March. Now Harry, Niall Horan, Liam Payne and Louis Tomlinson are holding down the forte as a four-piece and there are rumours they're no longer a solid unit.

There's constant gossip a break-up is imminent, which is also thought to be getting to Harry. His response is to go out and have fun, but this is just running him down.

"The pressure and uncertainty are getting too much for Harry," the source continued. "He needs to take care of himself but he just wants to party through everything."

Meanwhile, Zayn, who left the band because he wanted a "normal life", apparently isn't getting the calm he craves either. There's dispute over his supposedly leaked track No Type and it's thought to be a worry for the 22-year-old. His pal Naughty Boy claims MC Righteous leaked the song, but Righteous says Zayn wanted him to release it.

"He doesn't need this," an insider said. "It's freaking him out. He left One Direction to get away from this kind of stress, but now he's getting it from all sides. The last thing he needs is more trouble from the label and his friends fighting."