This weekend on The iHeartRadio Countdown with Mario Lopez we have a special guest host! Mario is out and his wife Courtney is in! She's giving Mario a little break this weekend for Father's Day and counting down the top 20 herself! She'll also be playing some throwback classics she picked out, talking all about the Lopez kids and much more! Plus can The Weeknd hold onto the #1 spot for yet another week!? Tune in to find out!