UPDATE:

Ed Boon, creative director for Injustice developer NetherRealm, has all but confirmed the announcement with this brilliant tweet:

The Internet is currently springing leaks like a doomed submarine. After Dead Rising 4 and approximately 100 Bethesda games (I'm rounding up, it was 4), it now looks as though Injustice 2 Polygon has been contacted by a "helpful tipster", who revealed an Injustice 2-branded poster showing The Flash facing off against a possibly Kryptonite-aided Batman:The limited edition poster is reportedly being sent to branches of GameStop, to be given to the first batch of those who pre-order the game.Injustice publishers Warner Bros. don't have a press conference at E3, but the success of the first game could well make it an appealing prospect for either Microsoft or Sony's own stage shows.We had our first sniff of a sequel way back in 2014, and Warner Bros. celebrated the first game's three-year anniversary only last week by announcing a Batman-themed smartphone

Joe Skrebels is IGN's UK News Editor, and if Batman's finisher isn't just his opponent getting hit by a car again then this game is already a failure. Follow him on Twitter