The new car is to be unveiled later this month with Aguilera, whose hits include 'Dirrrty' and 'Genie in a Bottle', to sing the song live for Mercedes-Benz at the car's launch.
The company said that the song's message is at the heart of the Mercedes-Benz A-Class brand: "follow your own star".
Aguilera, who is currently appearing in an ad for Virgin Mobile where she appears to be caught in a compromising position, said: "One thing that I've definitely learned is how important it is to follow my own heart, my own instincts and that, I can say, is what betters me every day."
There is already a dedicated , where an instrumental version of the song can be heard until the single is released on June 28, when it will be available on the site.
J Justus Schneider, director of worldwide marketing communications at Mercedes-Benz, said: "Nobody could have translated this motto into music as well as Christina Aguilera."
The ad campaign, created by Springer & Jacoby, Hamburg, will only be shown in markets where the A-Class is available.
If you have an opinion on this or any other issue raised on Brand Republic, join the debate in the .