ProjeKct X was a side project of the music band King Crimson during 1999–2000.

In 2000, while the band King Crimson recorded their album the construKction of light, the four members of this line-up also recorded the album Heaven and Earth as ProjeKct X. The line-up consisted of Robert Fripp on Guitar, Adrian Belew on Guitar and V-Drums, Trey Gunn on Warr Guitar, and Pat Mastelotto on traps and "buttons" (electronic percussion and loops).

This continued the tradition of ProjeKcts One, Two, Three, and Four (sub-groups into which King Crimson 'fraKctalised' from 1997 to 1999). Heaven and Earth is an album by ProjeKct X released in 2000 on the DGM label in the US and Germany and Pony Canyon in Japan The title track later appeared as the last track on the construKction of light.