Clara ( song ) " Clara " was an instrumental song composed by the Twelfth Doctor . He performed the song several times for Clara Oswald in her TARDIS , disguised as an American diner , during a visit to Nevada and , when asked by her if the composition had a title , identified it as " Clara " . This occurred after he erased most memories of his former companion , so he was unaware that he was playing it for Clara herself . The Doctor didn ' t know the origin of the tune . However , after discussing the fact that the Doctor no longer had specific memories of Clara , and in particular had forgotten a private message she gave him while in the cloisters on Gallifrey , Clara suggested that songs , such as this one , might represent those lost memories . The Doctor considered this and continued to play the song as Clara ' s TARDIS dematerialised around him . ( TV : " Hell Bent " ) Behind the scenes . In reality , " Clara " was composed by series music composer Murray Gold . It is a very rare case of a soundtrack composition — as opposed to a vocal song — becoming diegetic , or part of the narrative . Originally titled " Clara ? " and also known as " The Impossible Girl " ( the title it was performed under during the Doctor Who at the Proms ( 2013 ) concert and the Doctor Who Symphonic Spectacular ) , the composition was first heard briefly in TV : " Asylum of the Daleks " in 2012 during the sequence in which Oswin utters the phrase " Run you clever boy , and remember " for the first time . A full arrangement of the song was first heard on the soundtrack to " The Snowmen " in 2012 , most notably during the sequence in which Clara Oswin Oswald ascends to where the Doctor ' s TARDIS is hidden ; the soundtrack album for the special titles the track " Clara in the TARDIS " . The " Snowmen " version incorporates a wordless choral vocal singing the melody , which is unique to this version of the leitmotif . Prior to this , Gold had also composed " Oswin Oswald " , a musical theme for the earlier character . This tune had a similar melody , but a number of noticable differences to the later track . " Clara ? " , although introduced for Oswin and Clara Oswin Oswald , became the recurring leitmotif for Clara Oswald proper , beginning with " The Bells of Saint John " and was featured prominently in the opening minutes of the 50th anniversary special , " The Day of the Doctor " . It was also borrowed for the Red Button spoof " The Five ( ish ) Doctors Reboot " for a sequence in which Jenna Coleman , Matt Smith and Steven Moffat appear . It continued to be a recurring theme for Clara during Series 8 and 9 , before becoming part of the narrative in " Hell Bent " ; a sombre variant was featured during her death scene in " Face the Raven " . Besides being played on camera during " Hell Bent " in an electric guitar version by Peter Capaldi , the tune also was prominently featured in the Cloisters sequence where the camera pans away from the Doctor and Clara during their private moment . A narrative link is made between the use of the melody in that sequence and Clara later suggesting the song might represent what she said in the cloisters . Behind - the - scenes footage of Clara ' s farewell scene , included in the " Doctor Who Extra " instalment for " Hell Bent " reveals that Capaldi played the melody off - camera on an acoustic guitar as Coleman filmed her final goodbye to the Doctor . The theme also plays during a scene in " The Pilot " , when the Doctor is about to wipe the memories from Bill Potts ' adventure with him and she asks him to imagine what it would feel like if someone did it to him . According to " Doctor Who Magazine " # 512 , a deleted scene had the Doctor playing the melody on his guitar , on stage in a nightclub as the characters of Bill and Heather meet ; the episode , as finally broadcast , removed most of this scene in favour of a montage , with the " Clara " melody removed from the soundtrack . This scene was later broadcast on 1 July 2017 by BBC America , along with a second cut scene in which it is revealed the Doctor now refers to the song by the title " I Forget " ; this wiki ' s policy is to not consider deleted scenes as valid canon sources , so " Clara " remains the only canonical title given to this composition . Had it been kept in the final episode , it would have been a unique case of a companion being introduced as we heard " another " companion ' s leitmotif . This is not the first piece of music attributed ( in the fictional universe ) to the Doctor ; he previously conducted a fourth wall - breaking orchestral performance of another piece of music he created ( TV : " Music of the Spheres " ) and throughout the televised and expanded franchise , many references have been made to him either composing or contributing to the writing of other works , including some well - known compositions . It is also , after " Love Don ' t Roam " ( TV : " The Runaway Bride " ) , the second diegetic song to refer ( albeit in this case instrumentally ) to a lost companion , although " Love Don ' t Roam " , in - universe , just happened to be a song the Doctor heard being played in a night club with lyrics that invoked memories of Rose Tyler .