Alien Blue, one of the biggest and best third-party Reddit apps built for iOS, has been acquired by Reddit. It becomes the site's official app for iPhone and iPad, and its paid "Pro" upgrade — which was $2 — is now free to all users for a limited time.

Built by Jason Morrissey, who also created the popular third-party YouTube app Jasmine, Alien Blue has been a must-have for any Reddit user since it made its App Store debut way back in May 2010. It is most admired for its expansive feature set and impressive design.

The app has always been a free download for iPhone, but it offered a $2 in-app purchase that added a whole bunch of additional features, including HD thumbnails for those with Retina devices, the ability to block posts by keywords, and tilt to scroll.

Now all of those are free for one week — as is the Alien Blue app for iPad — in a new and official Alien Blue app that's available now.

"Our whole philosophy has been to give our users choice. We've got the reddit AMA app, and alienblue coming out… but we really want users to use whatever they want." says Ellen Pao, reddit's head of Strategic Partnerships, in a statement to TechCrunch.

"We think Alienblue is great, and it's the most popular reddit app on iOS. We wanted to be able to offer it as a reddit app, and we wanted to help Jase with additional resources to do everything he wanted to do with it."

Morrissey has now joined the Reddit team, and he will continue to make improvements and add new features to the Alien Blue app. He has also vowed to continue development of Jasmine, but there's currently no word on whether Alien Blue will be coming to Android.

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