Half-Life 3 has been long rumored to be in development, but during the Unity keynote speech at Unite 2013, it appears the game has been brought up, and perhaps confirmed.

"Unity is a game development ecosystem: a powerful rendering engine fully integrated with a complete set of intuitive tools and rapid workflows to create interactive 3D content," says the official website.

Currently, the Unite 2013 event is happening, and during the livestrem of the keynote by David Helgason, it appears that Half-Life 3 was mentioned at some point, causing several fans to take it as a sign of confirmation.

Is David announcing Half-Life 3 ?! #unity3d #unitytech

— Eric Batut (@_HerrDoktor_) August 28, 2013

Just switched on and I think @davidhelgason just announced Half Life 3 for @unity3d #unite13 — James Parker (@GamesWriting) August 28, 2013

For those who don't know, Unity is a tool that many mod users utilize to create their own mod, like the ones below.

Meanwhile, it appears that Valve may be working on Half-Life 3, but it is still in the early stages.

According to a Reddit user who recently took a tour of the studio, the game has "elements" in place.

"If I told you anything about it you'd just have more questions. We only have elements. Bits and pieces of game. No structure. No story," says the tour guide to the Reddit user.