A special edition of the iHeartRadio Countdown with Mario Lopez this weekend as Mario’s wife Courtney Lopez fills in for Mario who’s off shooting a new game show! Courtney will share a few of her favorite songs as she counts down Top 20 Songs of the Week & reveals a brand new number one! Plus, Jonas Brothers go K-Pop with our Next Big Thing, we fire up the time machine with our Throwback Track, Courtney shares more iHeartRadio Music Festival details, & more!