DeSantis, who has had two staff shake-ups in the past three weeks and is sinking in the polls, had long planned to attend the Iowa State Fair on Saturday, a political must for aspiring presidential candidates in the state that kicks off the Republican nominating contest in January.

Trump's late announcement on Tuesday that he was also going to attend the event on the same day as DeSantis amounted to a political gate-crashing of DeSantis' appearance, one the Florida governor hopes will kick-start his stalled campaign.

DeSantis is making a high-risk bet that he can halt Trump's march to the Republican presidential nomination by winning Iowa.

Iowa holds the first of the state-by-state Republican nominating contests on Jan. 15. DeSantis hopes that a win in the Midwestern state will give him valuable momentum against Trump before primaries in New Hampshire and South Carolina.

Trump's appearance at the Iowa State Fair just hours after DeSantis' could steal the limelight from the governor and dominate the headlines. The fair is held in the state capital Des Moines and runs from Aug. 10 to Aug. 20. Last year, it attracted more than 1 million visitors.

Trump's appearance will also complicate efforts for the rest of the Republican field. Apart from Trump and DeSantis, nine other candidates will be attending the fair between Aug. 11 and Aug. 18, but all are languishing in single digits, over 40 points behind Trump according to the latest Reuters/Ipsos poll of likely Republican voters.

According to that Aug. 3 poll, Trump also leads DeSantis by 34 points, 47% to 13%.

Most of Trump's rivals, including DeSantis, have agreed to be interviewed individually at the state fair by Iowa's Republican Governor Kim Reynolds between Aug. 11 and Aug. 18, but Trump turned down her invitation. Trump has been angered by her public neutrality in the primary race and her appearance with DeSantis at several of his Iowa events.