Instagram has released a chat app for Direct. Carl Court/Getty Images

Instagram has released a demo version of its standalone messaging app, Direct, in six countries including Italy and Portugal.

Direct would be separate from Instagram's main application and is similar to how Messenger was divided from the Facebook app.

The trial launched today (7 December) in Italy, Portugal, Chile, Israel, Turkey and Uruguay. There is no official timeline for releasing the app globally.

It would be the third messaging app owned by Facebook (joining Messenger and WhatsApp).

For those keeping a rough count, the most popular ways to message (including the three already mentioned) are text messaging, WeChat, Skype and Snapchat.

WhatsApp is the most popular, followed closely by Facebook Messenger. In third place is Chinese messaging app QQ Mobile.

Speaking to The Verge, Instagram product manager Hemal Shah said: "We want Instagram to be a place for all of your moments, and private sharing with close friends is an important part of that."

Instagram is using the same argument as Facebook did in 2014 to justify a standalone app. It says messaging through Instagram can never be a full experience so long as it lives in another app.

"Direct has grown with Instagram over the past four years but we can make it even better if it stands on its own," Shah said.

"We can push the boundaries to create the fastest and most creative space for private sharing when Direct is a camera-first, standalone app."