Fans miss Mary Berry as Bake Off viewers and celebrities are divided over line-up and advertsAn average of 6.5 million people tuned in to Tuesday night's episode, giving Channel 4 its highest overnight audience for five years, the broadcaster said. The figure includes those who watched the episode on Channel 4+1.
Bake Off's biggest overnight audience for a launch episode on BBC Two was 5.6 million in 2013.
By contrast the show's launch on BBC One last year won an overnight average of 10.4 million - almost four million above the figure for Channel 4.
Jay Hunt, Channel 4's outgoing chief creative officer, said: "The Great British Bake Off's audience last night proves it's still one of the country's favourite shows.
"I am delighted millions watched the new team put 12 magnificent bakers through their paces. It's the largest share of young audiences we've had for a show for over a decade."
During the Edinburgh International Television Festival last week, Hunt said she would be "absolutely delighted" if the new series of Bake Off was watched by "five, six, seven million" on the channel.
The series returned to television screens on Tuesday night with three new faces in its line-up: presenters Sandi Toksvig and Noel Fielding, as well as new judge Prue Leith.
Paul Hollywood was the only member of the original team to move with the show to Channel 4. He told BBC Radio 2 he had only "caught the last 20 minutes" of the launch show, but added: "It was great. All the reaction has been very, very positive, which is great news."
The first episode saw IT programme manager Peter, 52, get sent home. It also heralded the arrival of ad breaks, which were absent during the show's run on the BBC.
The episode's ratings of 6.5 million is nearly double the number recorded for Diana: In Her Own Words, which had been Channel 4's largest overnight audience so far this year.
It is also the highest overnight ratings enjoyed by Channel 4 since the opening ceremony of the London Paralympic Games in August 2012.
The figure is likely to rise higher when the official consolidated ratings are published next week, which will include people who recorded the show and watched it up to seven days afterwards.