Microsoft and HTC started to distribute a firmware update on Wednesday to enable Internet Sharing on original Windows Phone devices.

The HTC Mozart and the HTC HD7 both received prompts for a “HTC Update for Windows Phone” and a number of WinRumors readers have written in to confirm that Internet Sharing is now present on their devices following the update. Microsoft’s Windows Phone 7.5 Internet Sharing allows phone owners to create a wireless hotspot with their cellular data connection. The feature is new to Windows Phone 7.5 and a number of existing devices require firmware updates to enable it. Microsoft previously revealed that the feature would require updated Wi-Fi drivers for existing devices.

Nokia is also planning to distribute an Internet Sharing update to its Nokia Lumia 800 devices. The Lumia 800 went on sale on Wednesday and does not include the feature out-of-the-box. The Finnish handset maker confirmed to WinRumors that an update is on the way shortly to enable the functionality. The updates to existing HTC devices on Wednesday are part of a number of firmware updates being pushed out to existing devices to improve hardware settings and battery performance.

Thanks to WinRumors readers David W and cpuzder for the news tips