Live Nation executive chairman Irving Azoff responded to board chairman Barry Diller's resignation via Twitter this morning by saying:

"As usual the press reports are ridiculous. It was always Barry Diller's
intention to step down from LNE COB during first year after TM/LN
merger. I look forward to continue to work with him during his time on
the board. I thank him for the many years of dedication and loyalty to
everyone at TM."

Sources confirm to Billboard.biz that it was widely known the chemistry between Azoff and Diller left something to be desired, and there was speculation by many insiders the announcement might have been made even earlier than during the Tuesday board meeting.

Though sources said there was a clash between Diller and other board members over control of the music behemoth, Diller said in a statement yesterday, “I have always said, since the merger of Ticketmaster and Live Nation, that I only planned to stay as chairman through the transition and integration of the two companies. It’s been almost a year and I informed the board today that while there was no rush, the board should start the process now to appoint a new chairman.”