They can't do much without being swamped by screaming fans.
And when One Direction landed at JFK airport in New York to start rehearsing for Saturday night live, they were mobbed by hundreds of them.
Niall, Louis and Liam kept their heads down as they made their way through the crowds, while Harry stopped to sign autographs for his adoring fans.
But poor old Zayn, who was looking rather bewildered by all the attention, was mistaken by a bodyguard for a fan, and wrestled into a headlock.
But the Story of My Life singer didn't seem to be particularly bothered by the scuffle, nor did he appear to suffer any injuries.
The heart throb recently admitted he still tries to impress his fiancée Perrie Edwards - who he proposed to in August - by making sure he always looks his best.
Speaking to E! News, he said: "I do try to impress her still, I do try to do a bit of exercise.
"I don't want to completely let myself go."
We seriously doubt he'd be able to look anything but amazing, and we're sure the Little Mix star feels the same.
She recently claimed that her 20-year-old fiancé found it "harder" to adjust to life in the spotlight than his other band mates , but he has claimed while it was strange he is having "fun".
He added: "I don't think it's necessarily I have a 'harder' time with it. It's just something that took a bit of time for me to get my head around, which obviously is normal for anybody, I guess.
"It's not something that is a normal thing to be doing. So it took a bit of time for me to get used to it, but I am used to it now and it's fun. I'm having fun with it, so it's all good."
The tattooed singer is currently making plans for his upcoming wedding, while his fellow stars are focused on his stag do.
We're a bit worried about their ideas, with Liam Payne suggesting they should "kidnap" their friend for a bash featuring "real guns and real strippers" . (Uh... what?)
Poor Zayn. :(