Fifth Harmony is no longer a five-person girl group, as one of the most prominent members has chosen to leave the group.

Camila Cabello is no longer part of Fifth Harmony, the group announced via Twitter late Sunday night.

"After 4 and a half years of being together, we have been informed via her representatives that Camila has decided to leave Fifth Harmony. We wish her well," wrote remaining group members Ally Brooke Hernandez, Normani Kordei Hamilton, Dinah Jane Hansen and Lauren Jauregui.

It's not clear if Cabello informed her fellow bandmates before her "representatives" did that she intended to leave.

"You Harmonizers have been there with us since the beginning, you've supported us, you've rejoiced and cried with us, you've grown with us, and with your love and support, we will continue on," the foursome wrote to their supportive fans. "We are excited for our future, and we can't wait for what the new year brings. Harmonizers, we are in this together. We love you with all of our hearts. Love Ally, Normani, Dinah and Lauren."

Cabello has dabbled with projects outside of Fifth Harmony over the past few years, collaborating with Shawn Mendes on last year's hit single "I Know What You Did Last Summer" as well as this year's Machine Gun Kelly's "Bad Things". Her duet with Mendes with Platinum.

Cabello was put together with Hernandez, Hamilton, Hansen and Jauregui by Simon Cowell on the U.S. version of The X Factor in 2012. The group made it all the way to the finale, where they came in third place. However, Fifty Harmony has had the most success of any U.S. X Factor act by far, with several hit singles ("Worth It", "Work from Home", "Sledgehammer") and numerous award wins and nominations.

Fifth Harmony will go on as a foursome.