Trump has previously said that if he did attend, he likely would be the target of rivals.
The Reagan Library event in September also will be live streamed on Rumble.
The moderators have yet to be announced.
Donald Trump and other GOP candidates at the last presidential debate at the Reagan Presidential Library in 2015Photo credit should read FREDERIC J BROWN/AFP via Getty Images
That event was telecast on CNN.
Meanwhile, campaigns on Tuesday were given more details on the format for the first debate.
Martha MacCallum and Bret Baier will moderate the two-hour event.
Fox News is anticipating two commercial breaks an hour, running three to four minutes each.
They also have to have a minimum of 40,000 donors, and 200 in 20 or more states.
