Talk-show host Jimmy Fallon called presidential candidate Hillary Rodham Clinton a "tough mother" and pulled her hair at her invitation on "The Tonight Show."

Taping the show for broadcast Wednesday night, Clinton asked Fallon if he'd ever touched Republican rival Donald Trump's hair.

"You wanna touch mine?" she asked.

Fallon tugged her hair and declared, "It's real!"

Trump spent the evening taking part in a Republican debate, but references to him dominated Clinton's appearance on "The Tonight Show." The show began with Fallon wearing a wig, impersonating Trump in a sketch in which he schooled Clinton on handling interviews.

"Immigration: Wall or giant wall?" Fallon-as-Trump asked.

Clinton said America was built by people who "worked their hearts out. ... Do you have any idea what it's like to work so hard for something, to be so close to getting it but then someone pops out of somewhere and tries to take it all away?"

"Are you talking about Bernie Sanders?" Fallon, in Trump character, asked.

Later, back in his real role as show host, Fallon called Clinton "a tough mother," which made her laugh. "I wouldn't mess with you," he said. "You're like if Ronda Rousey shopped at Ann Taylor Loft." Rousey is a mixed martial arts champ.

Fallon repeatedly referred to Clinton as a mother and grandmother, saying at one point that the State Department email scandal should have been headlined, "Grandma knows how to use an email!"

Fallon told Clinton that if she would just "tell us what's in the emails," the scandal would go away. Clinton said the emails are "boring," with the most interesting one that's come to light about a request that she deliver gefilte fish to Israel in time for Passover.

Fallon also expressed surprise that Clinton uses social media, selfies and Twitter. "Do you know how to do all these things? You know what these things are?"

"It is the way to communicate," she said. "I actually like it."

"You took a selfie with Kim Kardashian," he said. "Did you know who Kim Kardashian was?"

"Of course I did," she said, adding that Kardashian and her husband, Kanye West, attended a fundraiser and were "just delightful." She recalled Kardashian saying, "You want to take a selfie?"

"I said, 'Sure.'"

Clinton also said she was "having a good time watching" Trump's campaign. She speculated that if Trump or Dr. Ben Carson, a retired neurosurgeon who is also running for the Republican nomination, became president, "you could have the White House renamed the Trump House and you could have Dr. Carson doing surgery in the basement."

She suggested that Trump as president might keep foreign leaders off-guard: "Imagine, you know, all of a sudden you are in the Kremlin. And somebody comes rushing in and goes, 'Oh, my gosh, did you hear what President Trump said today?' ... It might actually cause everybody else to calm down."

In the opening sketch, Fallon as Trump told Clinton: "I haven't seen you since my last wedding."

"I'm sure I'll see you at the next one," Clinton said. She then asked him, "What is your stance on women's issues?"

He responded, "I know a lot of women and they all have issues."

Fallon ended Clinton's appearance on a serious note, asking her to identify the issue that "defines" her, noting that Trump's issue is immigration, while big business is an issue for Clinton's Democratic rival Bernie Sanders.

"Raising Americans' income," she responded. "Getting more money into your paycheck so that you can have a better chance."