 The episode featured a large amount of incidental music . During Gwen 's hen night , the club she is in plays the tracks " Filthy / <unk> " and " <unk> <unk> " by the <unk> Sisters from their eponymous 2004 album and the single " Hole in the Head " from the <unk> 2003 album Three . The song heard on Gwen 's radio Alarm <unk> when she wakes up heavily pregnant is " Fire in My Heart " from the Welsh rock band Super <unk> Animals . At Gwen and Rhys ' wedding reception , the records played include " You Do Something to Me " by Paul <unk> and the song " <unk> Love " by Soft Cell . One of the black and white photos of Jack seen at the end of the episode is actually a promotional picture of John Barrowman from his role as Billy Flynn in the musical Chicago . 
