Brown said it was quite a step up from steering a single horse to now having 470 horsepower (351kW) available from the V8 engine of the LC 500.
"With my sporting background, I truly appreciate the rewarding and highly enjoyable driving experience of the LC 500 as well as its distinctive athletic profile," he said.
Lexus Australia chief executive Scott Thompson said Corey was a natural fit as the latest Lexus ambassador in a year in which Lexus has become the naming rights sponsor of the Melbourne Cup.
"His rich heritage in the sport of racing has continued to ignite the passion that comes from exhilarating performance and exceeding expectations - qualities that go hand in hand with Lexus," he said.
Brown's appointment as ambassador was made in the Lexus Design Pavilion at Flemington during media day for this year's Lexus Melbourne Cup.
Brown, chasing a remarkable third victory in the race that stops a nation™, has been booked to ride English stayer Magic Circle in this year's running of Australia's most prestigious annual thoroughbred horse race.