Between her gothic look and coy demeanor on the red carpet, Lorde can be pegged as a quiet introvert who is very serious about her craft. While the latter is unquestionably true, she came out of her shell a bit on 'The Tonight Show Starring Jimmy Fallon' last night (Nov. 25).

Dressed in a long red-to-black ombre maxi dress, Lorde is full of energy while she chats with Fallon about her friendship with Taylor Swift and curating the soundtrack for 'The Hunger Games: Mockingbird Part 1.' Watch the interview in the video above.

The two dish about how nice Swift is -- and Lorde reveals that their whole friendship started because the '1989' star sent the 'Team' singer flowers following the success of 'Pure Heroine.' The two then met over Shake Shack milkshakes, and the rest is history. Lorde even talked about the time they tricked some guy that she was Swift's manager during her first time at the Grammys.

"And all of a sudden, I was Taylor Swift's manager," Lorde said as she acted out the situation. "This like tiny, gothy, like hunched person [groan], and just had to pretend to be this person. And the worst part ... I performed that night on that stage about a half an hour later."

They also chatted about working on 'The Hunger Games,' which Lorde admitted to not knowing what she was doing. "I think [it took] two and a half months, which is abnormally short for a soundtrack," she said. "I was on the road, on the tour bus, and I would literally run offstage in my outfits, strip it off and then get into my bed on the tour bus and just start work for the day on this soundtrack."

Of course, Lorde couldn't stop by 'The Tonight Show' without getting behind the mic. And while she was a bubbly girl during the interview, her performance brought her back to the Lorde we all know and have grown to love. Wearing a similar -- or more likely, the same -- outfit that she wore at the American Music Awards a few days ago, she sang the song with such gusto, and even hair-flipped with the best of them.

Check out her performance of 'Yellow Flicker Beat' below: