Doctor Who's new assistant Jenna-Louise Coleman made a surprise early appearance in the first episode of the new series. Picture: Adrian Rogers/BBC/PA Wire

Audience figures for The X Factor dropped as Doctor Who returned to television screens.

Overnight ratings show the ITV talent show pulled in its lowest audience of the series so far, with an average of 8.6million viewers - including those watching on the +1 channel. The first two shows of 2012 had an average of 8.7m viewers. At this stage in 2011, The X Factor was consistently pulling in more than 10m viewers.

Doctor Who, which returned to screens with an episode called Asylum of the Daleks featuring a surprise appearance from the Doctor’s new assistant Oswin, saw a slight audience increase on last year’s launch episode.

The first episode of Doctor Who drew an average of 6.2m, which was 200,000 up on the last series when it began in August 2011.

The debut of Oswin, played by Jenna-Louise Coleman, had been kept secret despite a number of preview screenings.

Executive producer and head writer Steven Moffat thanked those who had attended for keeping her appearance a surprise.

“This show has been seen at four separate screenings, across four different countries and yet not one person gave one spoiler,” said Moffat.