"People are giving Rosie a hard time," Madonna, who starred with O'Donnell in 1992's "A League of Their Own," said Thursday on NBC's "Today" show. "I wish they'd stop. I don't think it's fair."
The 48-year-old pop star, who was promoting her new film "Arthur and the Invisibles," told "Today" co-host Meredith Vieira that O'Donnell was just doing her job as a stand-up comic when she insulted Trump.
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"I think all stand-up comics talk about provocative things in their monologues before shows, and I think that's a commonplace thing," she said.
Meanwhile, O'Donnell, moderator of "The View," has been in discussions about reviving her old talk show, The New York Post reported Thursday, citing unnamed sources.
Sources told the Post that O'Donnell, 44, has been talking to Warner Bros.' Telepictures division about reinstating "The Rosie O'Donnell Show," which was popular for most of its 1996-to-2002 run until ratings dipped toward the end.
The news came amid the ongoing hailstorm of insults fired back and forth between O'Donnell and Trump, which began last month after O'Donnell criticized Trump's handling of the Miss USA scandal.
Despite allegations that reigning Miss USA Tara Conner had besmirched the crown with her hard partying, drinking and drug use, Trump, 60 — who runs the pageant — decided to give her a second chance. In response, O'Donnell made fun of his hairdo on "The View" and said he shouldn't be the "moral compass for 20-year-olds."
On Wednesday the feud, which has also involved "View" creator and co-host Barbara Walters, continued. In spite of Trump's claims that Walters had been badmouthing O'Donnell to him, Walters and O'Donnell presented a united front on "The View," with Walters calling Trump a "poor, pathetic man" but never mentioning him by name.
In response, Trump released a statement in which he characterized the 77-year-old Walters as a "sad figurehead dominated by a third-rate comedian."
In a statement released by his organization Wednesday, Trump accused Walters of "taking the low road for the sake of her show rather than the sake of her morality."
Walters and O'Donnell opened Wednesday morning's live broadcast of "The View" by addressing a stinging letter penned and circulated Tuesday by Trump and addressed to O'Donnell in which he claims Walters "lied to both of us" about their ongoing squabble.
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Dropping a nationally televised bomb on Trump, Walters told O'Donnell that he "just can't let go."
O'Donnell responded with an enthusiastic shot of her own against Trump.
"His show tanked!" O'Donnell yelled to a cheering studio audience, a reference to reports that the season premiere of Trump's show "The Apprentice" finished a dismal third in Sunday night's ratings. "And on we go to things that are actually important!"
In his statement, Trump also refuted O'Donnell's claim (based on numerous media reports) that "The Apprentice" had done poorly.
"Rosie lied once again by incorrectly citing 'The Apprentice' ratings," Trump said. "Nielsen showed 'The Apprentice' was number one from 10:30 to 11:00 p.m. in all of television."
Cynics speculated that Trump's in-the-spotlight handling of the Miss USA scandal and his counter-attacks on O'Donnell were publicity stunts for "The Apprentice."
But the efforts seem to have failed. The program garnered 9.1 million viewers for a 5.4 Nielsen rating — low for a season-opener of the once popular NBC show and about half a million viewers behind the last "Apprentice" debut, according to Nielsen Media Research, which charted the show as coming in third place in its time slot.
Ratings for "The View," on the other hand, have been up since O'Donnell joined the show this fall and have risen again since she and Trump have gone head-to-head, according to Nielsen.
There have been conflicting reports about when her contract expires, with some reports saying June and others saying September.
Warner Bros. denied it was in talks with O'Donnell about bringing back her own show, according to the Post.
"We are not talking to Rosie O'Donnell," the paper quoted a spokeswoman as saying Wednesday.
Her publicist, Cindi Berger, told the Post that her contract was currently with ABC Daytime and "we don't know what her future plans will be at this time."
FOX News' Catherine Donaldson-Evans contributed to this report.
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