Avril voiced her support for Deryck Whibley on Twitter after he opened up about his battle with alcoholism from his hospital bed.
In a post titled 'Rock Bottom,' the 34-year-old Sum 41 rocker, who has been receiving treatment for a month, wrote: "The reason I got so sick is from all the hard boozing I've been doing over the years. It finally caught up to me.
"I was drinking hard every day. Until one night. I was sitting at home, poured myself another drink around midnight and was about to watch a movie when all of a sudden I didn't feel so good. I then collapsed to the ground unconscious."