This weekend on The iHeartRadio Countdown with Mario Lopez the very talented AJ Michalka will be stopped by the studio! She's one of the stars of ABC's 'Schooled' which is a spin off of 'The Goldbergs' which she also stars in. Plus she recently started making new music with her sister Aly again which you can check out below. So we'll catch up with her, countdown the top 20 songs in the country AND play some throwback classics. Tune in!