 The episode 's airing — in particular , its shock regeneration — contributed to a public surge of interest , described by Daily Mail journalist Paul Revoir as " Doctor Who fever " . The regeneration prompted a large amount of speculation to Tennant 's replacement : actor Robert Carlyle was the bookmaker 's favourite to replace Tennant ; and actors James McAvoy , Jason Statham , Alan Davies , and James Nesbitt were less popular predictions . In his article about the public reaction to the cliffhanger , Revoir offered five popular theories : a botched regeneration that resulted in two Doctors ; a revelation that the whole series was dream sequence like the ninth season of Dallas ; Tennant 's successor being female ; a normal regeneration ; and a cover @-@ up by the BBC to disguise the fact that " Journey 's End " would be Tennant 's last appearance ; the first theory proved to be correct . The increase of public interest peaked in the two days prior to the transmission of " Journey 's End " : the day before transmission saw the Seventh Doctor 's actor Sylvester McCoy , Collinson , Davies , and Agyeman appear on separate daytime television shows ; and coverage of the series finale was the top story in BBC News Online 's entertainment section several hours before transmission . Davies attributed the amount of interest the episode created — which was greater than he expected — and the success of the new series to the measures made in keeping plot details secret and creating a " live experience " : 
