The extra 15 minutes will mean that fans will still get an hour of the show, not including adverts.
Comedian Jo Brand has also announced she will join the channel with her spin-off programme, The Great British Bake Off: An Extra Slice.
Brand described herself "as a completely mediocre baker... but lover of all things spongy and tarty".
"I am really looking forward to another Extra Slice and all the fun and frolics that brings," she added.
Follow us on Facebook, on Twitter @BBCNewsEnts, or on Instagram at bbcnewsents. If you have a story suggestion email entertainment.news@bbc.co.uk.
The new Great British Bake Off is to extend to 75 minutes when it moves to Channel 4 later this year.