Microsoft-owned Skype said the trial is a preview version of Skype for Outlook.com and will allow Outlook users to make voice-over-Internet-protocol or VIP calls directly from their in-box, Mashable reported Wednesday.
"Even with the best email service, sometimes text isn't enough," Skype said in a blog posting. "We all face those situations where it's just easier to jump on a call to talk something through.
"Sometimes that quick call can accomplish more than a long email reply," Simon Longbottom, Skype's senior director of product marketing, said in the post.
A browser plug-in that supports the most recent versions of Internet Explorer, Chrome and Firefox will merge users' Skype and Outlook/Miocrosoft accounts.
To use Skype, users must click on the audio- or video-call buttons in an instant messaging conversation or above a friend's contact details in an email exchange.
After the roll-outs in Britain, Germany and the United States, worldwide availability will begin this summer, Skype said.