<P> The Face of Boe is a fictional character in the British science fiction television series Doctor Who . Not portrayed on - screen by an actor , the Face of Boe is a wholly mechanical effect , resembling a gigantic human - like head with a weathered face and in place of hair , numerous tendrils which terminate in round pod - like structures . Typically it is encased in a clear sealed container and mounted on a movable pedestal base . The Face merely grunted during his appearance in `` The End of the World '' , communicated telepathically in `` New Earth '' and `` Gridlock '' , and spoke for the first and last time in the latter , and was voiced by Struan Rodger . It is stated in `` New Earth '' that he is thought to be millions of years old ( billions , at least according to `` Gridlock '' ) ; however , when this was suggested to him , he responded with a leading question concerning the impossibility of such an age . It was suggested in `` Last of the Time Lords '' that the Face of Boe is a future Jack Harkness . </P>
when do you find out jack is the face of boe
Last of the Time Lords