Hidden inside the Apple Watch’s bottom strap connector slot is a mysterious six-pin port. While Apple has yet to confirm its purpose, it could come in very useful.

Accessory maker Reserve Strap has confirmed that the hidden port is not only suitable for charging, but will top up the Watch’s battery significantly more quickly than the included wireless charging dock.

The company’s new strap accessory is currently the only strap with a built-in battery that uses this port, letting it charge up the Watch while it’s being worn.

Compared to the likes of the LG G Watch R which lasts one and a half days with the screen always on, the Apple Watch falls short in the longevity department, so this could be good news for Watch wearers.

A special tool is included to provide access to the port, and we expect a flood of charging strap accessories to follow its lead in providing extra juice. You can pre-order the Reserve Strap here, for the princely sum of R3,000.

Whether or not Apple will disable the charging feature with a software update is another matter entirely. Watch this space.

Sorry.