Ariana Grande said it was a "special day" today (Sept. 3), and she wasn't kidding! Not only did her debut album drop -- and quickly hit No. 1 on iTunes in 30 countries including the U.S. -- but she and special guest Mac Miller performed on the 'Today' show.

Wearing a short and flirty white dress, Ariana celebrated debut album 'Yours Truly' with a pair of performances on the Plaza, singing 'The Way' and 'Tattooed Heart.' Asked beforehand by 'Today' co-host Savannah Guthrie if the album's quick success was exceeding her wildest dreams, the 20-year-old singer stated, "I was hoping it would do well, but I didn't expect it to go No. 1 so quickly. I'm so incredibly excited."

Rapper Miller joined her for the smash 'The Way,' goofing up the lyrics a little and earning some giggles from Ariana. A quartet of dancers and a pair of singers backed up the lighthearted performance. The throwback ballad 'Tattooed Heart' gave her big voice a big-time workout, but she definitely proved up to the task.

Ariana was clearly delighted by the fans who turned up to the Plaza, first giving them a shout-out on national TV ("Look how cute they are! I love you guys") before showing her love on social media:

This Instagram photo was posted with the caption "special day #YoursTruly" next to a pair of hearts:

Watch Ariana Grande Perform 'Tattooed Heart' on the 'Today' Show