Medal of Honor: Warfighter briefly tempted customers with access to a Battlefield 4 beta before being removed from the public eye, according to neoGAF. Interesting, since Battlefield 4 doesn't really exist or anything yet, at least not in any sort of publicly official capacity.
While we didn't see the advertisement on Origin with our very own eyes, it was reportedly live and functional as a promotion, if lacking specific Battlefield 4 details, according to a corroborating report from IGN. It's possible that this was an accidental admission of BF4's existence, but it's also possible that someone at EA has learned an important lesson about letting the interns near Photoshop. We've got out ears to the ground and will update with any new information.