Watch the BBC News video of the event (UK visitors only):
The game is good, the graphics are very good, and we look great.
The game, which goes on sale on 9 September 2009, is to feature 45 songs, along with a bonus track - All You Need Is Love - which can be bought online via Xbox Live.
Microsoft says all proceeds from the sale of the bonus song will go to Doctors Without Borders, the US branch of the charity Doctors Without Borders/Médecins Sans Frontières (MSF).
Additionally, the entire Abbey Road album will be available for purchase and download, along with other tracks from The Beatles' canon.
We love the game, it's fantastic.
Ten songs were announced during E3: I Saw Her Standing There, I Want To Hold Your Hand, I Feel Fine, Taxman, Day Tripper, Back In The USSR, I Am The Walrus, Octopus's Garden, Here Comes The Sun and Get Back.
The Beatles Rock Band includes a number of locations where The Beatles played, including the Cavern Club in Liverpool, The Ed Sullivan Show set, New York's Shea Stadium and the Budokan in Japan.
Content will also include previously unreleased recordings of The Beatles talking between takes during studio sessions recorded at Abbey Road.
Watch the official trailer:
The game will be sold alongside optional controllers based on the instruments played by The Beatles during the 1960s, including John Lennon's Rickenbacker 325 and Paul McCartney's Hofner violin bass.