Later in the evening, a surprise speaker will take the stage in support of Mitt Romney and Paul RyanPaul RyanRyan: Graham-Cassidy 'best, last chance' to repeal ObamaCare Ryan: Americans want to see Trump talking with Dem leaders Overnight Finance: CBO to release limited analysis of ObamaCare repeal bill | DOJ investigates Equifax stock sales | House weighs tougher rules for banks dealing with North Korea MORE — there is heavy speculation that the speaker will be actor, director and former Carmel, Calif., mayor Clint Eastwood, but the GOP had not confirmed that as of early Thursday morning.

Finally, Sen. Marco RubioMarco Antonio RubioOvernight Defense: Senate passes 0B defense bill | 3,000 US troops heading to Afghanistan | Two more Navy officials fired over ship collisions Senate passes 0B defense bill Trump bets base will stick with him on immigration MORE (Fla.), who was seen as a potential running mate for Romney, will introduce the presumed nominee, who will officially accept the nomination and close out the convention.