The Beatles: Rock Band the masters to come in and just author them ... its like, send people to Abbey Road, use the original tape, separate them out ... it costs thousands of dollars." Drake asserted that Harmonix would take sales of the currently announced albums into consideration before continuing development of downloadable content. Harmonix's Foster stated that solo acts from the Beatles' members will not be included as downloadable content for "The Beatles: Rock Band"; however, he did not rule out the possibility of these acts appearing in other "Rock Band" games. A three pack of songs from Paul McCartney's 2009 live album,
The Beatles "Dizzy Miss Lizzy"; they were the last covers the band would include on an album, with the exception of "Let It Be" brief rendition of the traditional Liverpool folk song "Maggie Mae". The band expanded their use of vocal overdubs on "Help!" and incorporated classical instruments into some arrangements, including a string quartet on the pop ballad "Yesterday". Composed by and sung by McCartney – none of the other Beatles perform on the recording – "Yesterday" inspired the most cover versions of any song ever written. The group's third US tour opened with a performance before a world-record crowd of