Demi Lovato is really working on her hip hop cred!

The 19-year-old singer/actress has duets with Missy Elliott and Timbaland on her upcoming album, Unbroken (available Tuesday), and now she's taking her talents to the stage!

Lovato covered Lil Wayne's smash hit "How to Love" at her show at New York City's Hammerstein Ballroom last night -- and fans went crazy (even when Demi forgot some of the lyrics!) Watch above.

Demi also posted a new video message to her fans about how much she loves them (get it??). In the vid, called "A Letter To My Fans," she credits them for helping her through her recent tough times. Says Lovato:

    "Last year everything stopped and for the next three months I woke up in a treatment center every day, away from my family and friends. ... I thought about the sadness that I felt, the pain that I was in and the addictions that I was struggling from."