The host and his guest even faced off in a little game of "Name That Tune," one that nearly went off the rails when Cyrus had some serious trouble recognizing one of her biggest hits.
Here's what you missed from her "Tonight Show" appearance:
Liam's Sexy's Rescue Mission
Speaking about the fires that tore through Malibu and her own home, Cyrus pointed out that while many people lost so much, it's been wonderful seeing the community working together to "rebuild such a magical place."
"When you remember things you loved and lost, whether it's photos, or old Elvis records or something my dad's given me, it doesn't make it easier," she explained. "But being able to go back, rebuild this together, be stronger together ... it's given a really beautiful light at the end of something pretty dark."
Cyrus was actually out of the country when the fires were happening, leaving Liam Hemsworth to go on a mission to rescue the many animals on the compound.
"Liam was an amazing hero. He got out all the horses, the pigs, seven dogs, four cats. It was really sexy to me," she explained. "I was like, you got pigs and horses and cats and dogs! He was kind of, he was trying to make me feel better because I wasn't there."
"He's Australian, so he's a little intense," she continued, before throwing on an Aussie accent. "He goes like this, 'Babe, I'm just dominating the evacuation! Look at it, I got the bigs in he back, they're int he crates!"
Her Stoner Family
It's so secret that Miley enjoys a little recreational marijuana use from time to time, but she's not the only one in the family.
"My mom's a big stoner," she told Fallon. "I remember when I started smoking weed, she thought I was like growing little horns and just becoming the devil and now she smokes more pot than anyone I know."
She added that both Tish and Billy Ray Cyrus smoke together, before "they play with these hummingbirds" around their home. "It's very sweet," added Miley.
Miley's Big Fail
If there's one thing music artists become familiar with through the course of their career, it's their own songs, and yet Miley Cyrus took way too long to identify one of her own hits in a game with Jimmy Fallon Thursday night.
Granted, this wasn't one of her most recent hits, but considering that she's probably played it literally hundreds of time in concert and heard it a ton more on the radio, you'd think she'd be able to pick up its signature beat and rhythm almost instantly.
It all went down during a game of "Name That Song." Miley was all fired up for this one, after she felt somewhat robbed by Jimmy during the first round. Nevertheless, they were both stumped when The Roots started performing one of Miley's biggest hits one instrument at a time. Finally, she did buzz in and identify it as "Party in the U.S.A," but Fallon still wasn't impressed.
"It took you that long to get that one?" he laughed. "I wish I had a number one song they could play."