The core of the theory has been kicking around for years among Lavigne fans, but the gist of it is that when Lavigne first became famous, she disliked all the attention and so hired an incredibly convincing look-alike named Melissa Vandella to distract paparazzi. During a time when everyone was supposed to celebrate Mother's Day, a conspiracy theory on Twitter has brought out a group of truthers.
The company then began using Melissa as the real Avril - who then apparently begins leaking details of Avril's death via song lyrics, album booklets, and promotional materials, including clothing.
The blog was set up to "prove how easy it is to start a big internet conspiracy theory", according to BuzzFeed reporter Ryan Broderick whose reporting on the blog in 2015 accidentally spread the rumour.
To make it worth going viral, Dr Rosewarne said a conspiracy theory must have the "right ingredients" - namely some humour, a celebrity and the right setting. There was even a photo of Avril from a photoshoot with the name Melissa written on her hand.
"I'm really happy to announce that I am now working on new music and I will be releasing a new album in 2017", she wrote in an Instagram post.
According to the Sun, a blogger said: "Launched in 2004, it is completely different to the first CD!" She has been since 2003, after the release of her much-loved album Let Go, when she took her own life following the death of her grandfather.
She is now working on a new album.
Over the weekend, the world learned with great regret that pop-punk icon Avril Lavigne had passed away.
And it's not just physical features that users believe have changed - others are were suspicious when Avril promoted a slimming bar as a "yummy and healthy snack". Ms. Lavigne has an active presence in social media and her latest tweet on May 14 is one made in the framework of the Mother's Day celebration. "The jig is up Melissa" which garnered more than 15,000 retweets.
Avril herself has yet to comment on the conspiracy theory.
Earlier today fans of the 'Sk8er Boi' singer were dragged back down the rabbit hole when the theory blew up again on Twitter, of course!