Song written by Midge Ure and recorded by Midge Ure and Kate Bush as a duet for Midge's album 'Answers to nothing', which was released by Chrysalis records in August 1988.
According to Midge Ure in an interview on WFNX in Boston in January 1989, he met Kate Bush at a social event and passed on a tape of the song to her and told her that he'd like her to participate. She called him back a couple of days later and said that she was very moved by the song and that she'd do it, but he had to send her all the tapes, and that she'd add her vocals herself. She then called Midge back a week later and told him that she was finished.
There are several versions of the song: the album version and two single edits. Although 'Sister and brother' was never released as a single, an edit, clocking in at 4'12, was made and finally released on a 1998 reissue of the album on CD. A 2010 reissue of the album features an 'alternate single edit', which is 4'46 minutes long. Finally, this 2010 reissue also featured two 'work in progress mixes', but on these versions there are no vocals by Kate Bush.