Meghan Trainor gave you bass, so you best not be cheating on her.

At least that's her message in her brand-new doo-wop-tinged song, "Lips Are Movin," which premiered at MeghanTrainor.MTV.com. The "All About That Bass" singer gives us another up-beat, catchy ladies' anthem that seems destined to be another hit for the 20-year-old newcomer.

On the song, the MTV Artist to Watch discovers that, after exchanging his sweet talk for her bass, her boyfriend is cheating on her, and now she's saying "goodbye bye bye."

"I know you lie because your lips are movin/ Tell me do you think I'm dumb?/ I might be young, but I ain't stupid/ Talking circles with your tongue," she sings on the track. "I gave you bass/ You gave me sweet talk/ Saying I'm your number 1/Bbut I know you lie because your lips are movin/ Baby don't you know I'm done."

Meghan's been on a hot streak as of late. "All About That Bass," is #1 on Billboard's Hot 100 charts, she's tapped John Legend to appear on her upcoming debut album, she just shot the video for her next single, "Title," and she earned a New Artist of the Year 2014 American Music Award nomination.

Listen to "Lips Are Movin," and get ready for more of Meghan Trainor's musical domination.