 Lettmann stated in an interview that she started modeling at the age of 16.She was first discovered in New York City at the age of 17 by Ford Models, which resulted in her moving from Germany to Paris at the age of 19 on her own to pursue her modeling career.In 2003, after working for a number of years in Paris, Lettmann worked on the Dunhill worldwide campaign with Mathias Vriens as photographer.