UPDATE: Camila responded to Fifth Harmony's message with a note of her own this afternoon on her Twitter.

"I was shocked to read the statement the Fifth Harmony account posted without my knowing. The girls were aware of my feelings through the long, much needed conversations about the future that we had during tour. Saying that they were just informed through my representatives that I was 'leaving the group' is simply not true," she writes.

Read it in full below.

Camila Cabello has left Fifth Harmony, according to a note posted by the girl group on Twitter at midnight (Dec. 19).

"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," the note — written by remaining members Ally Brooke, Normani Kordei, Dinah Jane and Lauren Jauregui — begins.

"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 note reads.

"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."

Only hours before (Dec. 18), all five members of the group performed together at Y100's Jingle Ball 2016 at the BB&T Center in Sunrise, Florida.

Cabello is currently sitting in the Top 10 on the Billboard Hot 100 with her solo song "Bad Things" with rapper Machine Gun Kelly. Only an hour before Fifth Harmony's Twitter announcement, Cabello retweeted news of the song going gold in the United States. She also performed the song solo at the Y100 Jingle Ball with Machine Gun Kelly.

Back when Camila teamed up with Shawn Mendes on "I Know What You Did Last Summer," the singer faced criticism from some fans who felt she was gearing up to jump ship for a solo career — which she vehemently denied at the time.

“It’s been very difficult to watch people criticize me and my intentions. It’s been sh–ty. They turned me [doing the song] into a conspiracy theory. We literally just wrote a song backstage, and it ended up becoming something awesome. It wasn’t a career move that I carefully planned out," she told Seventeen earlier this year.

There was, also, the not-so-uncommon visible tension between the group members visible during their promotions:

And also this:

Back in September, Cabello left the stage mid-show during a Fifth Harmony concert due to anxiety.

“We’d be lying if we all said this is a picture-perfect thing, like we all completely agreed on the album track list and what the sound and the music video treatment would be like, which usually happens in bands who grew up together...but for manufactured bands, it’s harder," she told Latina in 2015.

"At the end of the day I think it’s really important that we have respect for the fact that we are a group and we’re in this for one thing, but at the same time we each have our personal interests and we allow ourselves to pursue that," she said in a Border Crossings interview that same year.

See photos of Camila's final performance with Fifth Harmony at Y100's Jingle Ball, plus her solo performance with Machine Gun Kelly:

Fifth Harmony Through the Years, from X Factor USA to Today