The band was set to appear at the launch, according to The Irish Times, though they said they wouldn't actually play. The launch began at 1pm ET.
Rumors about the band taking part had been floating about for weeks but denied by their official spokeswoman.
However, it appears she was incorrect when she stated that “They are not releasing their album on the iPhone and they are not performing at the iPhone launch.”
The band rocked out at the launch - and now all iTunes customers are getting their new album, Songs of Innocence, for free.
The album is now available in everyone's iTunes account.
It now appears that a recent U2 appearance in a video shot on the Samuel Beckett Bridge in Dublin was related to the Apple launch. There was very high security at the event with umbrellas being used to shield what was being filmed.
U2 has worked previously with Apple. They appeared in the first ads for the iPod in 2005 and the new iPhone 6 will come preloaded with the Beats sound system. U2's members are close to the founders of Beats, Jimmy Iovine and Dr Dre.
The new phone has been described as a “game changer” for Apple still suffering the loss of genius founder Steve Jobs. It is expected to be much larger than existing iPhone models.