"Comprised mainly of romantic gems recorded between 1997 and 2004, Love Songs features "Nuclear," the first new Destiny's Child recording since 2004. Produced by Pharrell Williams (who cowrote the track with DC's Michelle Williams, James Fauntleroy and Lonny Bereal), "Nuclear" features vocal production by Beyoncé and Lonny Bereal."
Wait if these facts are correct, Michelle (and others) wrote this song without involvement of Kelly and Beyonce? Interesting!
It seems kind of silly to release just one new song after all these years. Maybe they're using is to test the waters. If the single does really well maybe they'll come back full fledged.