Apple has been long rumoured to be working on a smartwatch, and recent hires as well as the company's growing interest in health and fitness-tracking would suggest that we might see something sooner rather than later. If "people familiar with the matter" speaking to the Wall Street Journal are to be trusted, we could even see multiple versions with different screen sizes.

The paper says the wrist device is likely to be launched in the fall and will pack more than 10 sensors. Although no specific features were discussed in the report, the device is expected to have a strong focus on health and fitness.

One source at a component supplier said shipments of the smartwatches are estimated to total between 10 and 15 million units by the end of this year.

The claims about having multiple screen sizes do sound a bit unlikely for Apple, which is usually all about streamlined product lineups, doing fewer things but doing them well. It could be that they're still experimenting with different form factors in house, or perhaps they are going a different route seeing as watches are fashion accessories and one design might not fit all.

A separate Reuters report recently talked about a single 2.5-inch screen device with wireless charging and pulse sensing capabilities.

Apple has been hinting at new product categories for a while and most are putting their bets on something TV-related and wearables. Just last month at the Code Conference, media chief Eddy Cue teased that the roadmap for upcoming products is the best he's seen in his 25 years at Apple.