Will and Jaden Smith may star together in their upcoming sci-fi flick After Earth, which they’ve been promoting like craaaazy, but it's music we're interested in today. We’re putting them against each other for a late night rap battle!

Will stopped by The Late Show With David Letterman while his 14-year-old son hung out at Late Night With Jimmy Fallon last night. Sure, they both talked about their movies and other miscellaneous topics, but one thing also went down for the father and son –- they both rapped on the shows!

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Will walked out on Letterman to his classic hit “Summertime” being played by the show band, which led him to give an impromptu performance! (Rare for him these days, that's for sure.) We thought we'd just hear Will talk about his movie but we got a surprise mini-concert along with that!

Jaden, on the other hand, waited until the end of his appearance to show off his rapping skills. After talking about After Earth, skateboarding and his clothing line, Jimmy asked Jaden to team with their The Roots for a song!

Rapping with your dad has to be a pretty cool thing, but even just having him be one of the biggest stars in Hollywood has to lead to plenty of advice. “Probably the best advice he’s ever given me is, ‘Don’t have a girlfriend,’” Jaden revealed. “The stress is real.”

Will, being the hilarious guy that he is, laughed and added, “At this point, I just want him to establish his dreams, establish his desires. Find out who he is. And blending with another person is very difficult, and lot of times you can lose yourself in the process. So my encouragement to him is to be honest with anybody that he interacts with. Don’t make commitments that a 14-year-old can’t live up to.”

You can see how Will and Jaden interact on the big screen when After Earth hits theaters on May 31st!

Whose rapping skills were the best on late night TV? Will or Jaden’s?