Hosted by actor/comedian John Leguizamo, Nickelodeon's Mega Music Fest will feature celebrities like Colbie Caillat, Wyclef Jean, and The Roots performing never-before-seen duets with Dora the Explorer, the cast of 'Yo Gabba Gabba!', and Kai-Lan, plus special appearances by The Laurie Berkner Band, The Fresh Beat Band, and even a few surprise cameos. John Leguizamo will need YOUR preschooler's help to make sure the show goes on!
| Actor | Role |
|---|---|
 John LeguizamoSelf | Self |
| CCaitlin SanchezDora Marquez (voice) | Dora Marquez (voice) |
 Donovan PattonJoe/Bot (voice) | Joe/Bot (voice) |
 Jon BeaversTwist | Twist |
 Thomas HobsonShout | Shout |
 Shayna RoseMarina | Marina |
 Yvette Gonzalez-NacerKiki | Kiki |
| LLaurie BerknerSelf | Self |
 Justin BieberSelf | Self |
 Phil McGrawSelf | Self |
 Colbie CaillatSelf | Self |
 Wyclef JeanSelf | Self |
 Sofie ZamchickLinny (voice) | Linny (voice) |
 Teala DunnTuck (voice) | Tuck (voice) |
| DDanica LeeMing Ming (voice) | Ming Ming (voice) |
 Traci Paige JohnsonBlue (voice) | Blue (voice) |
| RRegan MizrahiBoots (voice) | Boots (voice) |
 Lance RobertsonDJ Lance Rock | DJ Lance Rock |
| JJade-Lianna PetersKai Lan (voice) | Kai Lan (voice) |
 Sherri ShepherdSelf | Self |
| JJeanine PetersThe Chicken | The Chicken |
 Donna PieroniThe Crossing Guard | The Crossing Guard |
 Emerald-Angel YoungPiano Player | Piano Player |