UPDATE with more info: President Donald Trump will have to find a seat-filler for tomorrow’s meeting with business leaders that make up his President’s Strategic and Policy Forum. Disney CEO Bob Iger will not attend the White House sit-down so he can join a scheduled board meeting at Disney headquarters in Burbank, a source tells Deadline.

The White House did not respond to request for comment on Iger’s absence.

It should be noted that Iger was never formally included on the list to attend tomorrow’s meeting. Many people assumed, however, he would attend because he’s one of the CEOs on the Forum.

The development comes as several groups lobby Iger along with other heads of big companies to speak out against Trump’s immigration ban. Several tech execs including Netflix’ Reed Hastings, Facebook’s Mark Zuckerberg and Apple’s Tim Cook, as well as CEOs of Starbucks and Coca-Cola, have already done so.

Today, in fact, Uber’s CEO Travis Kalanick told his employees he would exit from the forum amid criticism from workers and customers.

Netflix’s Hastings on Saturday called Trump’s order “so un-American it pains us all. Worse, these actions will make America less safe (through hatred and loss of allies) rather than more safe….It is time to link arms together to protect American values of freedom and opportunity.”

Tesla’s Elon Musk, a member of the Strategic and Policy Forum, said on Twitter that the ban “is not the best way to address the country’s challenges” and would seek a “consensus” to “present to [the] President.”

At the same time, a corporate watchdog group called SumOfUs has circulated a petition asking Iger to join them — and chastising him for being “dangerously silent.”

“We know that most CEOs support immigration, and almost all have employees that will be impacted by the ban – but swayed by Trump’s new position, they are afraid to speak out publicly and looking after their own interests and profits over the basic human rights of their employees, customers and vulnerable refugees,” the group says. “Making matters worse – they continue to validate Trump’s violent agenda by serving on his advisory council. This is unacceptable.”

Tomorrow’s two-hour business advisory panel meeting, arranged by Blackstone Group’s Stephen Schwartzman, is due to begin with an address by the President.