The exoplanet is 110 light-years from Earth and was discovered by NASA's Kepler spacecraft in 2015.
A year on these planets flies by, lasting between five and 10 Earth days.
The planet is likely the densest Earth-sized planet ever found.
The spacecraft has spotted almost three-quarters of the alien planets scientists have identified to date.
The news is under tight wraps, but spoiler alert: It's definitely not Nibiru.
The lipstick-shaped satellite has already done incredible science, whatever news Thursday's announcement brings.
The device will look for stars like our own sun and examine planets similar to Earth.