The 64-year-old comedian joins a group of stars filling in for the 58-year-old host as he will be "taking the next two months off - this time voluntarily" - referencing when ABC pulled the show off the air for six days in September 2025.
During Kimmel's montage on Thursday's episode of the ABC talk show, he said: "We have assembled a potent group of hosts to fill in for me, beginning with Tiffany Haddish, Colman Domingo, Ike Barinholtz, Anthony Anderson, Jelly Roll."
The comedian then gave a shoutout to O'Donnell, adding: "And, as a special treat for our commander-in-chief, I asked one of his all-time favourites, Rosie O'Donnell, to be here to keep the hits coming."
As the audience laughed and clapped, Kimmel added: "You're welcome. And all I ask in return, Mr President, is that you don't do anything stupid while I'm gone. OK?"
Kimmel did not reveal when O'Donnell would host, but her representative confirmed to Entertainment Weekly that her one week guest presenting gig begins on August 17.
O'Donnell took to Instagram on Friday and posted a screenshot of a link to People's article about fronting Jimmy Kimmel Live!, with the caption: "And I can't wait !!! #jimmykimmellive."
Kimmel spoke sarcastically when he referred to O'Donnell as one of US President Donald Trump's "all-time favourites", since she and the Republican Party politician have been publicly feuding since 2006.
It started when Trump - who owned the Miss USA pageant at the time - announced at a press conference that the then-Miss USA Tara Conner would keep her crown despite accusations of partaking in underage drinking and cocaine use.
O'Donnell criticised the businessman's press conference for being self-serving, and jokingly compared Trump to the "snake-oil salesman on Little House on the Prairie", on an episode of ABC's The View - a show she is willing to return to as a guest host.
The dispute intensified in July 2025 after Trump publicly suggested he would seek to revoke O'Donnell's citizenship, despite lacking the constitutional authority to do so.
O'Donnell relocated to Ireland in January 2025 following the 2024 US presidential election.
Despite the move, she returned to the US on June 7 for the Tony Awards in New York City.
O'Donnell is set to pop back to the United States in July to perform her one-woman Broadway show, Common Knowledge.
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