The Rolling Stones are putting three songs from their new album on sale via digital download, three weeks ahead of the album's release.
There are 16 songs on the Rolling Stones' forthcoming album
Rough Justice, future single Streets of Love and Back of My Hand will feature on September album A Bigger Bang.
Described as "an ambitious collection of hard-hitting, high-powered rock and blues songs", A Bigger Bang is the Stones' first studio album since 1997.
The band begins its 40-date world tour in Boston on 21 August.
The new songs are being sold by "all major" download retailers, where prices vary, the band said.
Metal band Metallica are to support the Stones at their San Francisco shows on 13 and 15 November.
"We thought it might be fun to play a few small intimate gigs so we called up our close personal friends, the Rolling Stones," said a message on the group's website.
"Seriously, how could we say no to the quintessential rock band?
"These two shows are about nothing more than having fun and playing music. (We have) nothing to sell, nothing to promote, nothing to talk about."
Black Eyed Peas, Maroon 5, Pearl Jam and British soul star Joss Stone are among the other acts lined up to support the Stones on the US leg of their tour.