The sponsorship includes the spin-off show Bake Off: An Extra Slice as well as festive episodes.
When Channel 4 kicked off its search for sponsors in April this year, the sponsorship packaged was estimated at £8m.
The deal was brokered between Channel 4’s commercial team, 4 Sales, and Lyle's media agency M/SIX and MEC, for Dr Oetker. Creative agencies Iris and Cheetham Bell will create the brands’ respective sponsorship idents.
Both brands are main sponsors of the show. The 20-second opening and closing bumpers will be split 50:50 with ten-seconds each per brand. The centre-break bumpers will be rotated equally between the two partners.
The partnership with Lyle’s Golden Syrup follows its sponsorship of weekend mornings on Channel 4 in 2016, which marked its return to TV advertising for the first time in 25 years.
Dr Oetker’s sponsorship of The Great British Bake Off is the first time the baking brand has ever sponsored primetime TV programming.
Jonathan Allan, sales director, Channel 4, said: "We’ve had such a great response from a huge range of advertisers wanting to feature in the series, including our new cross-platform superspots and the creative launch ad-break."
Paul Hollywood was the only member of the original BBC lineup to follow the show to Channel 4 when it controversially scooped the rights in Septemberlast year. The TV chef and cookery school founder Prue Leith will join him on the judging panel, in place of Mary Berry.
Sandi Toksvig and Noel Fielding will replace hosts Mel Giedroyc and Sue Perkins.