Microsoft, which owns Skype, said Monday that Skype users can ask Alexa-enabled speakers to make free online calls to other Skype or Alexa users. To do so, callers must sync their Skype accounts to their Echo speakers

If users have an Alexa-powered speaker that has a video screen, like the Echo Show, they can also ask Alexa to make video calls with other Skype users.

Additionally, Microsoft said it would give Skype users 200 free minutes to make Skype calls from their Echo speakers to “most landlines and mobile numbers internationally.” Typically, Skype users must pay to make online calls to landline and mobile phones.

In a blog post detailing the new Skype feature, Microsoft only mentioned Amazon’s Echo speakers, so it’s unclear if people who own Alexa-enabled smart speakers from other manufacturers can also make Skype calls.

Fortune contacted Microsoft for more information and will update this story if it responds.

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Separately, Amazon is trying to popularize online calling using Alexa directly, rather than through Skype. In March, the company said that people could use Alexa to make free online calls using their iPads, Amazon Fire tablets, and other Android-powered tablets, as long as those devices have the Alexa app installed.

Update: Nov. 19, 2:05 PM, PT.

A Skype spokesperson said that Skype is “working to bring” the new calling feature to third-party Alexa-powered devices, but didn’t reveal a date.