miley cyrus cnn gi Miley Cyrus' plunging neckline draws eyes at CNN Heroes eventMiley Cyrus looked ultra glam on the arm of boyfriend Liam Hemsworth at Sunday’s (Dec. 11) CNN Heroes: An All-Star Tribute event at Los Angeles’ Shrine Auditorium.

The 19-year-old sported some serious cleavage in an otherwise sweet Roberto Cavalli gown. Her hair was cute in a loose side-braid. She topped off the ensemble with Neil Lane jewels and Alaia heels.

Miley later changed into a much more conservative royal blue gown to take the stage and perform “The Climb.”

“What a glorious night to be apart of,” tweeted Cyrus from the event. “Thank you for having me on your stage @CNN Such an honor.”

On Monday, after changing her Twitter profile photo to one from the event, she tweeted:

“How cute did Liam look last night?!?! ! I felt like one of those cartoons all night w/ big hearts flying out of my eyes!?”