Along with Ferrari, Lamborghini and Maserati, Alfa Romeos personify the image of Italian motoring with their sporty overtones and curvaceous lines, however some of the brand’s most admired models were in fact created by an American designer. Now, less than a year out from Alfa Romeo’s official return to the U.S., American Frank Stephenson, has quit his role as chief designer.

Cars developed under his guidance include the first Alfa Romeo in years to be headed for the U.S., the new 8C Competizione, which is due to arrive early next year, as well as the recently revealed Mi.To hatchback, one of the most stylish compacts we’ve seen in years. Other cars he’s played a role in creating include the first-generation BMW X5, new Mini Cooper, Maserati’s Quattroporte and MC12 supercar.

Speaking with AutoWeek, the designer confirmed his resignation but wasn’t willing to state his reasons. “I have a few things I am looking at now, but I don’t want to go into them, but it’s something that I have instigated,” Stephenson said.

Many suspect Stephenson is leaving to make way for former Pininfarina design director Lorenzo Ramaciottim who has been hired by Fiat Group CEO Sergio Marchionne as the carmaker’s new design chief. However, Stephenson denied such claims, explaining that Lorenzo is “a fun guy to work with.”

Stephenson will officially be replaced by 40-year-old Austrian designer Christopher Reitz.

Alfa Romeo Mi.To