Simon Cowell: One Direction Are 'Really Nice Boys'

Louis Tomlinson waves to fans as he and his One Direction band mates arrive for their concert at the Scottish Exhibition and Conference Centre on Tuesday (February 26) in Glasgow, Scotland.

Louis, 19, and the rest of the guys – Harry Styles, Liam Payne, Niall Horan, and Zayn Malik � were recently praised by their boss Simon Cowell.

PHOTOS: Check out the latest pics of One Direction

“They are the most grounded artists I’ve ever worked with,” he told Heat magazine. “They’re really nice boys, so there are no tantrums. It’s my job to make sure they are happy.”

A few days earlier, One Direction kicked off their “Take Me Home” tour at the O2 Arena in London, England.