Though the anniversary date was last month and Hale has preferred to keep her personal struggles to herself, the actor said that she believed it was important to send the message on Valentine's Day, as many people often face deeper feelings of loneliness on the holiday.

"While this journey has mostly been private, I felt compelled tonight to let anyone who is struggling know that you are not alone and you are loved," Hale said.

Many of Hale's celebrity friends congratulated her on the achievement, as Demi Lovato wrote: "I'm so proud of you sis. I love you so much. Thank you for being a part of my journey and allowing me to be a part of yours."

Lili Reinhart praised the milestone as "So amazing," with Debby Ryan adding that she's "so excited for the world to fall in love with the truest version of you."

Hale, now 33, made the decision to stop drinking in 2017, when she told Byrdie that she had "no interest" in being part of the Hollywood party scene any longer.

"Becoming a part of this popular show…everyone just says yes to you," Hale said at the time. "So, you get away with a lot, and then you make mistakes."

She added: "I'm just always trying to surround myself with better people ... and be the best version of myself possible."