Singer Demi Lovato was transported to Cedars Sinai Medical Center in Los Angeles Tuesday following a suspected overdose, sources familiar with the incident told NBC News.

First responders were called to a residence in the 8000 block of Laurel View Drive in the Hollywood area, the sources said. They used Naloxone, also known by its trade name Narcan, to reverse the effects of the overdose.

This past March the 25-year-old celebrated maintaining six years of sobriety. Lovato has for years been open about her battles with drug and alcohol addictions, as well as with bipolar disorder, eating disorders and self-harm. She underwent rehab in 2010, at age 18.

As news of Lovato's condition spread friends and fellow celebrities took to social media to express their best wished.

In June Lovato released a surprise track "Sober" about relapsing. The singer had been sober for six years prior to her relapse, leading to the surprise release of "Sober," in which she apologizes for letting down herself, her family and her fans.

In the ballad, she sings, "Mama, I'm so sorry I'm not sober anymore / And Daddy please forgive me for the drinks spilled on the floor / To the ones who never left me / We've been down this road before I'm so sorry, I'm not sober anymore."

"And I'm sorry for the fans I lost who watched me fall again," she also sings in "Sober." "I wanna be a role model / but I'm only human."