The Digitimes report cites sources in the Taiwanese-based supply chain that say "production of components has begun in small volumes" for a thinner MacBook.
The new model is expected to launch either later this year or by the end of 2015.
Apple has been reportedly working on a 12-inch MacBook Air with a high-resolution Retina display, though it is unclear if this thinner model would be part of Apple's MacBook Air or its MacBook Pro lineup.
Any announcement of a new MacBook launching this year would likely take place after Apple's upcoming September 9th event, where the company is widely-expected to unveil the iPhone 6.