Harry Styles, Liam Payne and Louis Tomlinson aren't the only members of One Direction working on songwriting with other artists. Niall Horan is collaborating and who with won't be a shock.

Horan is working with the guys from the U.K. band McFly -- Dougie Poynter, Danny Jones and Tom Fletcher.

That's not a new collabo, as Fletcher has written songs for previous 1D albums, as well as other hits, and Jones produced a song for the boys, as well. They keep things all in the extended family!

Below are the gushy tweets between Niall, the McFly guys and one of the McFly guy's girl! Georgia Horsley is Jones' fiancee.