The Take That frontman, 44, said he wouldn't think twice about joining the boy band if he was asked because he's desperate to team up with the 21-year-old heartthrob, reported Female First.
Asked if he wants to become the fifth member of the popular boyband and work alongside Styles, Barlow said, "He is the one... I know all of them but I know him better than the others. There's definitely no plans (to join) but, yeah, I would. If he asked me, I would, definitely (join the group).