Google announced on Tuesday that it has begun offering its Google Voice testers the opportunity to invite friends to join the telephony service.

In the next few weeks, Google will gradually add an invite a friend link to the left-hand side of Voice users' inboxes. Google will initially provide Voice users with three invites, but that number will expand in the future, the company said in a blog post.

The tech-giant said it will provide three invitations to current users that allow recipients to establish their own Google Voice accounts. The service remains in private testing mode.

The service itself is still on a invite-only basis, but people can request an invite at google.com/voiceinvite.

Google Voice made headlines recently when AT&T accused Google of skirting FCC rules regarding call connections. Last week Friday, the Federal Communications Commission announced that it would investigate AT&T's claims. Google denies any wrongdoing.