Janet WILL be appearing on Justin Timberlake’s new album, JUSTIFIED. A spokesperson for Justin Timberlake could not confirm the name of the song that Janet appears on, but said that the track is not a duet. Justified was produced by the Neptunes and Timbaland, and the entire album was co-written by Timberlake.
It is therefore an assumption that Janet will appear on an interlude on the album.