Game front has a story on the rumor. The rumor comes about as a screenshot showing new Multiplayer characters, including Protheans

An Anymous poster has posted more details about this. Makeing claims, some make sense, others dont. Free dlc? and EA?

Possible Spoilers

"The ending was half-assed because of the leak. They changed it at the last minute so they could have more time to prepare the real ending via DLC." "It’s called The Truth and it’s being released in April or May. You WILL be able to continue the story if you picked any of the endings. Your decision during that sequence will have a big effect on your ending of The Truth. The Truth adds two new sets of enemies, new classes, and multiplayer maps including “Firebase Hive”, which is a small area of the last remaining collector ship included in the DLC, which, by the way you should definitely bring Javik the Prothean along if you have him." "The picture here shows some of the leaked multiplayer classes and races. One race that isn’t shown is the Prothean Adept and Vanguard. This DLC also enables the ability for owners of the preorder and From Ashes DLC to find their DLC weapons in reinforcement packs." "All that content, and this might as well be labeled an expansion pack." "And it’s free." "You’re welcome."

I personally just had such a revelation talking to my friend about the whole thing on ME3, that the ending is open and that EA is loving the anger of a new ending and already have in place to SELL you the ending. Aswell as this Child play chipin retake the ending is all done by EA the maniacal genius they are. This Rumor ring similar to my theory except FREE? realy EA and the word FREE?

http://www.gamefront.com/rumor-mass-effect-3-dlc-the-truth-due-in-april/