Microsoft has added integration for Google’s Chat platform into Outlook.com, in a rare co-operative effort between two firms vying for search and web application dominance.

Redmond said on Tuesday that it would be allowing users to access Google Chat directly from their Outlook.com and SkyDrive pages. The platform will use the OAuth syncing protocol to connect with Google Chat and pull contact information to the Microsoft communications platform.

Once synced, users will be able to connect with and message friends on Google Chat through their Outlook.com homepages.

The move marks a rarely-seen gesture of co-operation between what has become one of the web’s most heated corporate rivalries. With Microsoft’s move into the search market with Bing and cloud application space with Office 365, the two firms find themselves directly competing on platforms ranging from communications apps to productivity suites.

That competition has been heated in the past, and Microsoft’s ‘Scroogled’ campaign essentially accused Google of selling off user data wholesale to third-party advertisers.

According to Microsoft, however, the Google Chat integration was less about outreach to Google than an effort to accommodate new users who have fled Gmail for Outlook.com. In a company blog post, Microsoft’s group program manager for connected services Douglas Pearce said that the company has similar integration components with other social networking platforms.

“You see this in the People experience, where you connect to your contact lists from Facebook, Twitter, LinkedIn and more,” he explained. “And you can already chat with your Facebook and Skype friends. But we heard that some of you who switched over from Gmail still want to chat with friends stuck on Gmail.”