Alyson Stoner reflected on their Camp Rock days in a newly released memoir - and spoke candidly about some highs and lows with former costar Demi Lovato. In Stoner's book, Semi-Well-Adjusted Despite Literally Everything, they recalled becoming fast friends with Lovato, 32, at a Camp Rock audition where they read for the roles of Caitlyn and Mitchie. "I oriented to Caitlyn's character profile, quickly memorizing lines and analyzing the beats of the scene," Stoner wrote in the book, which hit shelves on Tuesday, August 12. "Demi and I went page by page and found an instant rapport like childhood buddies. There was something so innocent about her demeanor, and it brought out the part of me that wanted to encourage her as an industry veteran." Stoner noted they were "lock and key" in the rehearsal, which made it easier when standing in front of the casting directors. MK Sadler "I knew the moment we entered the audition room, Disney would see our magic and cast us: Demi as the lead, and me as the sidekick," Stoner shared. Stoner further wrote that they and Lovato had a bond like no other when filming the first Camp Rock movie, which was released in 2008. However, things shifted after Camp Rock 2. Demi Lovato Through the Years Stoner recalled experiencing Lovato's addiction and mental health struggles during the 2010 Jonas Brothers: Live in Concert tour. They also detailed the night Lovato punched backup dancer Alex Welch. Keep scrolling for more about Stoner and Lovato's relationship: A Shared Experience Stoner and Lovato hoped to "support" each other as they both experienced struggles with food and disordered eating. "A byproduct of policing my own behaviors was inadvertently assessing others' habits," Stoner wrote, explaining that they "noticed" Lovato eating "freely" when they went out to dinner but going to the bathroom after every meal. (Lovato has spoken candidly about battling an eating disorder over the years.) "Nobody else noticed, but something unsettled me. Is she doing something to hurt herself? Would she be mad if I checked on her?" Stoner wrote. "She confided in me that she sometimes purged what she ate through self-induced vomiting. Having never dealt with that, it was scary to hear. From my health research, I knew the damage that bulimia could cause to the body, and my heart ached with care." Lovato revealed that she noticed Stoner's exercise routine, which they wrote "was growing more rigid and strenuous" at the time. "If I didn't follow the ideal meal plan, guilt and shame sent me straight to the gym until I reached a calorie deficit," they wrote. John Medland / Disney Channel / Courtesy Everett Collection A Shift in Behavior Stoner recalled Lovato "spinning in a tornado of substances and self-harm" ahead of the 2010 Jonas Brothers: Live in Concert tour. "Her moods swung unpredictably from euphoric to furious to dejected," Stoner wrote. "Whereas during the filming of the first Camp Rock she confided in me about her struggles, secrecy had since taken the reins." They said Lovato had started to cope with "reckless partying," which caused Stoner to wonder: "Where is my friend?" Experiencing the Addiction Stoner recalled "nearly 20 sober companions" being hired by Lovato's team to "monitor her behavior around the clock and guide her toward health and well-being." It's been widely reported - and confirmed by Lovato herself - that she continued to use substances. "At the time, she lied straight to our faces," Stoner wrote. "Because there was no explanation for her behavior (which would later be diagnosed as bipolar disorder, cross-addiction, depression, bulimia, and complex PTSD), there was no medication or treatment protocol in place, and she hadn't yet become self-aware or set the intention of recovery." Demi Lovato Recalls 'Experimenting' With Opioids at 12 After a Car Accident Demi Punching the Backup Dancer Lovato's sobriety journey started after she infamously punched backup dancer Welch during the Jonas Brothers tour. "Someone revealed that Demi was doing illegal drugs. In reaction to being called out, she coerced the managers into telling her who snitched," Stoner wrote. "I was standing in the aisle of the plane that would fly us to our next tour stop when Demi charged in, irate. There was a bloodthirsty look in her eyes. She stormed in my direction. My muscles tensed in fear, preparing to be berated." Stoner remembered that Lovato "suckerpunched" Welch before "the plane went still." Eventually, "terror gripped the cabin" with dancers checking on Welch. "I was a deer in headlights, struggling to grasp the scene unfolding before me," Stoner wrote. "The jet bridge was redrawn and the flight crew and tour executives began exiting and entering the plane. The rest of us waited in the wake." This prompted her first stint in rehab. (Lovato has addressed the incident publicly on various occasions over the years.) The Aftermath of the Incident Stoner wrote that fans "made signs demanding we apologize