Microsoft has announced that Skype-to-Skype calling is rolling out to its first "ambient device", the Harman Kardon Invoke speaker with Cortana.

• Harman Kardon Invoke speaker has Microsoft Cortana for brains

Skype is already available on PCs, smartphones, Android Wear and Xbox consoles, but now it's being integrated into a speaker for the first time.

You can speak voice commands to the Invoke speaker to call friends, family and local business contacts you have in your Skype account, such as "Hey Cortana, call mum" or "Hey Cortana, call the local pharmacy".

If you call someone else's Skype account, then calling is completely free but if you're calling through the Invoke speaker, then you can call mobile and landline phones completely free of charge too.

This feature is only available to US customers calling phones in the US, Canada, Mexico, Puerto Rico, Guam, American Samoa, Northern Mariana Islands and the US Virgin Islands.

These new calling features for the Invoke speaker are in addition to the functions it can already carry out, such as controlling smart home products compatible with Cortana, controlling music playback and setting reminders.

With the Invoke speaker being made by Harman Kardon, we'd like to assume audio quality will be high-quality, although it's difficult to say without hearing it. It also features an all-metal build and is available now in the US in Graphite or Pearl Silver colours for $200.