With release of the video, the Republican nominee finds himself mired in fresh scandal at a crucial point in the campaign, with just one month until Election Day on November 8 and barely 48 hours before he and Clinton face off in their second presidential debate.
Trump's fellow Republicans and Democratic foes alike swiftly condemned the obscene remarks caught in footage obtained and published by The Washington Post.
But Clinton may face harsh criticism as well, after anti-secrecy website WikiLeaks published thousands of hacked emails sent to and from her campaign, a document dump that appears to have made public the contents of several of her paid speeches.
Clinton is seeking to become the nation's first female commander in chief, and the former secretary of state is almost certain to call out Trump over the troubling video footage in their Sunday showdown.
Trump's coarse language, shocking even by the standards of this year's campaign, comes at a critical time for Trump, as he trails his Democratic rival in national polls and women, furious over his series of demeaning comments, are seen overwhelmingly backing Clinton.
The three-minute video captures Trump bragging about groping women with impunity and trying to have sex with someone who was already married.
"When you're a star, they let you do it," he says.
"Grab them by the p****y," Trump adds. "You can do anything."
![A screen grab of the video published by The Washington Post revealing Donald Trump's conversation with Billy Bush on board an](http://img.astroawani.com/2016-10/41475901409_freesize.jpg)
The tape was shot as Trump arrived on the set of daytime soap opera "Days of Our Lives," for a taping of a segment in which he was to have a cameo appearance, the Post said.
In the video, he was speaking with Billy Bush, then host of the "Access Hollywood" show about celebrities.
"I moved on her and I failed. I'll admit it," the billionaire Trump is heard saying in the video, then using an expletive for how he tried to have sex with her.
"Whoa," another voice says.
"I moved on her like a b***h, but I couldn't get there. And she was married," Trump says.
The tape was recorded in September 2005, months after Trump married his third wife, Melania, according to the Post.
Trump also remarks about an actress he was about to meet as they got off the bus.
"I've gotta use some Tic Tacs, just in case I start kissing her," Trump says.
'Horrific'
House Speaker Paul Ryan said he was "sickened" by the remarks, and disinvited Trump from a political event in Wisconsin.
"I am sickened by what I heard today. Women are to be championed and revered, not objectified," he said.
"I hope Mr Trump treats this situation with the seriousness it deserves and works to demonstrate to the country that he has greater respect for women than this clip suggests."
Minutes later, Trump's campaign said his vice presidential pick Mike Pence would be attending the event instead, while Trump would prepare for his showdown against Clinton on Sunday with Republican National Committee chairman Reince Priebus, New Jersey Governor Chris Christie and Alabama Senator Jeff Sessions.
With Trump's campaign clearly in damage control mode, he issued a rare apology, although he took a swipe at Clinton's husband, former president Bill Clinton, in the process.
"This was locker room banter, a private conversation that took place many years ago," Trump said in a statement.
"Bill Clinton has said far worse to me on the golf course -- not even close," he added. "I apologize if anyone was offended."
Clinton issued damning criticism of Trump's comments.
"This is horrific. We cannot allow this man to become president," she posted on Twitter.
Priebus, the Republican committee chair, said "no woman should ever be described in these terms or talked about in this manner. Ever."
Former Florida governor Jeb Bush, who lost to Trump in the primaries and has not endorsed his onetime foe, called Trump's comments "reprehensible."
Clinton email revelations
Clinton, meanwhile, was facing revelations from emails published by WikiLeaks, including a January message from a staffer to campaign chairman John Podesta and other top aides, that appeared to highlight several passages in her closed-door speeches to big banks and corporations.
"I'm not happy about being hacked by the Russians in their quest to throw the election to Donald Trump," Podesta wrote on Twitter, after US officials earlier formally accused Moscow of directing cyber attacks to "interfere" with the US election process.
"Don't have time to figure out which docs are real and which are faked."
Clinton's speech contents were points of contention during the Democratic primaries, as she refused rival Bernie Sanders's calls for her to release the transcripts.
The email, with the subject line "HRC Paid Speeches," contains what appears to be pro-trade excerpts from a May 16, 2013 speech to Brazil's Banco Itau.
"My dream is a hemispheric common market, with open trade and open borders, some time in the future with energy that is as green and sustainable as we can get it," she said, according to the email.
The comments may be used against her by Republicans, particularly after she expressed opposition to a sweeping trans-Pacific trade deal negotiated by President Barack Obama's administration.