Zayn doesn't really want to be a megastar so he ain't becoming the next JT or Bruno Mars. If PILLOWTALK was released by some unknown artist it would not have 10% of the success it's getting right now lbr.
I don't see him becoming huge like Justin Timberlake or Beyoncé.
Maybe bigger than Nicole Sherizinger.
It's Scherzinger... Sc-her-zinger
Zayn is already is bigger than Nicole. Whatever U Like deserved to smash, but it only charted low in a few countries. Pillow Talk is already #1 in multiple territories.