The X Factor 2018 launched down on last year's viewing figures, according to the first ratings.
However the opening episode of series 15 was still the most watched programme on TV on Saturday night.
Overnight data released this morning suggests that the first audition show of 2018 was seen by a total audience of 5.7 million viewers on the night.
That's down 500,000 on last year's opener in viewers but the show's audience share of 34% was up on 2017 by two share points.
This year sees another huge revamp to the series with Simon Cowell joined by new judges Robbie Williams, Ayda Williams and Louis Tomlinson.
The format has also been refreshed, with auditions back in the arenas while bootcamp has been axed in favour of a new 'judges deliberation' round before the six chair challenge.
The X Factor was by far the biggest show on TV last night and had at least 2 million more viewers than any other ITV show.
Big Stars Little Star concluded its series with 2.2 million viewers before 3.6 million watched Celebrity Catchphrase before X Factor.
After, The Jonathan Ross Show's new series began with 2.2 million viewers.
Meanwhile over on BBC One, Casualty's latest episode was seen by 3.8 million viewers, the most watched show of the night for the channel.
Celebrity game shows Impossible and Pointless had 2.4 million and 2.7 million viewers respectively.
On Channel 5, Celebrity Big Brother's dramatic highlights had 1.3 million tuning in.
Recent X Factor launch ratings
2018: 5.70 million
2017: 6.20 million
2016: 6.80 million
2015: 7.65 million
2014: 9.50 million
2013: 8.78 million
2012: 8.09 million
The X Factor 2017 auditions continue tonight at 8PM on ITV.
Next week the show will be back on both Saturday and Sunday again at the same time.
However Saturday's show will face stiffer competition as Strictly Come Dancing launches.
The Strictly opener starts at 7:35PM and will overlap with The X Factor between 8:30PM and 9PM.