She told E! News: "You guys will have to wait and see. I'm the biggest at top secrets. I've had this single ["We Can't Stop"] ready for about a year, and I've had to keep my lips sealed and just not saying anything. So you'll see."
Bieber is currently working on new music and is known for teaming up with some of the hottest names in music, so it's no stretch that he and Miley may be working together. His manager Scooter Braun told MTV News last month that the pop star was immersed in writing while on his "Believe" tour.
On Sunday night, Bieber took home two trophies at the Billboard Music Awards for Top Male Artist and Top Social Artist. He also won the Milestone Award.
Meanwhile, Cyrus' new track drops June 3. It's the first single from her much-anticipated 2013 album. She told Billboard: "Me and Mike Will teamed up, and it really just turned out to be perfect and exactly what I wanted, and exactly what I wanted my first sound to be, and my first look to be."
She's been making headlines recently for her on/again, off/again engagement to actor Liam Hemsworth. For those keeping track, she's been wearing her engagement ring despite postponing the wedding. Bieber's on/again, off/again relationship with Selena Gomez has also been a hot topic of late.