Sproull says she is looking forward to the "wild ride - fuelled by sugar, icing and lots of cream".
Award-winning baker Brettschneider and renowned chef Fleischl bring their expertise to the judging table.
"I can't wait to get cracking on the show and to see and nurture all the great home bakers," said Brettschneider, who's known internationally as "the Global Baker".
Trained at the Savoy Hotel in London and with over 20 years experience heading up The Great Catering Company, Fleischl is also looking forward to seeing what culinary delights the contestants whisk up in weeks to come.
"I'm so excited to be a judge alongside the very talented Dean Brettschneider," she said.
Based on the same Love Production format as the popular UK version, the show will see the Kiwi contestants take on a different baking skill each week until there's only one left standing.
Originally hosted by Sue Perkins and Mel Giedroyc, The Great British Bake Off has made stars out of both the hosts and judges Paul Hollywood, Mary Berry and Prue Leith, and inspired multiple versions to pop up around the globe.