Exclusive: Former royal pop star couple Selena Gomez and Justin Bieber may reunite at the upcoming Radio Disney Music Awards. Both Gomez and Bieber are set to appear at the event, which will be held April 27 at Nokia Theatre L.A. Live. Gomez, Bridgit Mendler, Denise Richards, R&B artist Jason Derulo, Jessica Sanchez, Nascar Daytona 500 Champion Trevor Bayne, Zendaya and Bella Thorne are among the presenters, while Bieber and Ryan Seacrest will make special appearances. Gomez, Cher Lloyd, Mendler, Cody Simpson, Mindless Behavior, Austin Mahone and Coco Jones are also scheduled to perform. Other presenters include YouTube’s Austin Mahone, Debby Ryan, recording artist Ariana Grande, Tatyana Ali, Laura Marano, Ross Lynch, Maia Mitchell, China Anne McClain, Olivia Holt, Jeff Corwin, Fifth Harmony and IM5. Nominees include One Direction, Taylor Swift and The Wanted. Both Gomez and Bieber made headlines this past weekend, Gomez with her racy performance at...