Simon Cowell is very, very nervous about One Direction's followup to 'Take Me Home.' What's got SiCo shaking in his shoes?

The boys' songwriting skills! The band are penning a ton of tracks for the new album, and Cowell is pretty nervous about relinquishing control -- but also somewhat excited to see what they'll come up with on their own.

"A lot of the tracks have been written by the guys this year and I'm always kind of nervous about that, but I have to tell you, their writing is absolutely brilliant," Cowell told Will Best (via SugarScape).

He continued, "Really, really good in so much that some of them are going to be singles, but really, really cool records, so they feel much more part of this album, I think."

As for what to expect from the new album's sound, Niall Horan told GQ (via Entertainment STV), "We don’t actually have a specific date for the new album, but on the road we will have more time to record and try things out. It’ll be heavier. A bit rockier," he promised. "A bit cooler."

Brace yourselves, Directioners! It's gonna be a good one.