Viewing figures for the opening episode, which include those who watched on catch up, show that a total of 10.8 million viewers tuned in.
A further 1.1 million watched repeat showings on Channel 4, E4 and 4Seven.
It makes it the biggest Channel 4 broadcast since modern records began in 2002. Going back further, it’s the biggest non-film broadcast since 1985’s Woman of Substance.
Furthermore, the audience of 2.8 million 16-34 year olds and a 61.4% share of the young demographic makes Bake Off it the biggest programme for young viewers on any channel so far in 2020 - outside of addresses from the Prime Minister.
The Great British Bake Off airs on Tuesday nights at 8PM on Channel 4.
Prue Leith and Paul Hollywood are once again the judges of The Great British Bake Off this year.
It's their fourth year together on the show since the series moved from BBC One in 2017.
Meanwhile, new co-host Matt Lucas replaces Sandi Toksvig, joining returning presenter Noel Fielding.
Alongside the main show, spin-off show Great British Bake Off: An Extra Slice airs on Fridays at 8PM on Channel 4, hosted by Jo Brand.
You can watch episodes on TV and online via All 4.