The Canadian megastar is poised to release her first new music in several years, with this new track due for a full release on September 19.
Overnight she posted a clip of the track on social media, teasing its defiant lyrics.
“I’ve gotta keep the calm before the storm,” she sings, “I don’t want less, I don’t want more.
“Must bar the windows and the doors, to keep me safe, to keep me warm.”
Lavigne, who rose to fame with songs like Complicated and Sk8er Boi, wrote on her website last week about her long road to releasing her sixth studio album, following a battle with Lyme Disease.
“Thank you for waiting so patiently as I fought through and still continue to fight, the battle of my lifetime,” she said.
“The first song I am choosing to release is called Head Above Water. It is also the first song I wrote from my bed during one of the scariest moments of my life.
“I had accepted death and could feel my body shutting down. I felt like I was drowning. Like I was going under water and I just needed to come up for air.”
She added: “I have decided to be truthful about my struggle, open and more vulnerable than ever before.
“And to be honest, part of me doesn’t want to talk about being sick because I want it to all be behind me, but I know I have to. Because not only is it a part of my life, I need to bring awareness to the severity of Lyme Disease.
“A single bug bite can f**k you up hard. People aren’t aware that Lyme must be treated almost immediately.
“Often if they are aware, they go untreated simply because they can’t get a Lyme diagnosis! And even when they do get a diagnosis, a lot of times they simply can’t afford the treatment.
“Here. I now have a very strong, triumphant, powerful and true record to me and my experiences over the last few years.”
Lavigne’s last album was her self-titled record back in 2013, featuring the singles Here’s To Never Growing Up and Rock’N’Roll.
It peaked at No4 in Canada, no14 in the UK and no5 in the US.
Head Above Water by Avril Lavigne is out on September 19.