WASHINGTON – The 2016 Democratic presidential nominee Hillary Clinton said Tuesday night that she did not understand the change she has seen in former New York Mayor Rudy Giuliani in recent years, joking that it seemed as if "aliens had seized his brain."

She made the comment after "Late Late Show" host James Corden asked Clinton if she had been surprised by Giuliani's behavior.

"Totally," she said, laughing. "He was mayor during 9/11. I was a senator, I worked with him, and I don't know what happened. It's almost like aliens have seized his brain."

She said Giuliani, who is acting as President Donald Trump's personal attorney, "has been saying things that were demonstrably untrue."

'America's mayor' to Trump's pit bull: Rudy Giuliani emerges as central figure in Ukraine firestorm

Is he a 'foreign agent'?: Trump-Ukraine scandal puts spotlight on Rudy Giuliani's business ties

Hillary Clinton is worried Rudy Giuliani may have had his brain seized by aliens 👽 pic.twitter.com/IpkAkJZPjq — The Late Late Show with James Corden (@latelateshow) November 6, 2019

Clinton cited his claim that he never saw her at ground zero after the Sept. 11, 2001 terrorists attacks, despite photographs of the two of them together at the site the day after the terrorist attacks that toppled the World Trade Center.

After that incident, Clinton said she remembered thinking, "truly he's been possessed."

"I don't understand when it happened but it is a very clear case of a man who has gone over the edge – probably pushed," she said.

"We need an exorcism," suggested Chelsea Clinton, who appeared with her mother on the CBS late-night talk show.

Giuliani has been at the center of the impeachment inquiry into allegations that Trump pressured Ukraine into opening a pair of investigations, one of them into former Vice President Joe Biden. Democrats say Giuliani was conducting a "shadow foreign policy" in Ukraine to carry out the president's wishes.

Story continues

The former New York City mayor has made several animated media appearances in defense of Trump since the president took office.

Some of his statements, such as his declaration that "truth isn't truth" were widely lampooned and in other instances, he has appeared to reveal more than he intended, such as when he said Trump had used his own money ahead of the 2016 election to buy the silence of a woman alleging an affair with the former reality TV star.

'Truth isn't truth': Trump lawyer Rudy Giuliani worries Mueller interview could lead to perjury charge

More: Rudy Giuliani accuses Twitter of anti-Trump conspiracy, editing his tweet to add typo

More: Rudy Giuliani says Trump is 'honest' because facts are 'in the eye of the beholder'

This article originally appeared on USA TODAY: Hillary Clinton jokes Rudy Giuliani's brain was 'seized by aliens'