Former President George H.W. Bush plans to endorse Mitt Romney, further urging the Republican Party to coalesce around the former Massachusetts governor's presidential campaign.
Romney spokeswoman Gail Gitcho says the two will meet Thursday in Houston.
They plan to appear together and speak to reporters.
Formal backing from the 41st president shows the Republican Party is uniting behind Romney while pressure builds on challengers Rick Santorum and Newt Gingrich to leave the race.
The elder Bush has offered encouraging words to Romney throughout the primary season but had yet to officially offer his support.
Former first lady Barbara Bush has formally backed Romney.
She recorded automated telephone calls for him during the primary in Ohio.
Former Florida Gov. Jeb Bush, a son of the president, endorsed Romney last week.