Of course Mass Effect 3 will have day-one single player DLC. The "bonus character and mission" included with the special edition of the game will be available for all to purchase. Given the significance of the content, it seems like hardcore Mass Effect fans will be unable to resist buying the add-on.
Kotaku first uncovered the DLC via a leaked Xbox Live Marketplace listing. The add-on, called "From Ashes," will allow players to "uncover lost secrets from the past." BioWare later confirmed on its forums that From Ashes will be available "at launch for all platforms."
Mass Effect 3 will be available on March 6th. Here: the extended CG trailer for the game, to distract you from the spoilers that are at the bottom of the post.
BOOM video 11931
Spoiler Alert: From Ashes will allow players to "recruit the Prothean squad member in Mass Effect 3." Voice files for the character were discovered in the audio files from the PC demo. You can listen to the character here.