Fallon added an extra challenge by enlisting the help of Roots member Questlove, who picked the most "undanceable" slow jams from the 1970s he could think of for the host and singer to quickly dance along to. Fallon and Lopez exchanged turns hilariously dancing as if upbeat tunes were playing instead of sluggish-tempoed songs like "Babe" by Styx.
More of Lopez's speedy moves can be seen in her flashy new video for her latest single, "El Anillo." The song -- which translates to "The Ring" -- is an all-but-subtle hint at the commitment the pop star wants from her boyfriend of over a year, former New York Yankees player Alex Rodriguez.
"The song is definitely about that, it is," Lopez admitted. "But I felt like it's something that all women get to a point where they say, 'OK, what's up?'"
Fallon chimed in, mentioning that he didn't propose to his wife until after three years of dating, even though he seemed to have known early on she was "the one."
"I feel like you know fairly quickly," Lopez added. "But don't go by me, I make tons of mistakes!"