The 'Hello Kitty' hitmaker and the Nickelback frontman, who denied their relationship was on the rocks last year, have confirmed their separation with "heavy hearts," but insist they are still "the best of friends."
In a statement on her Instagram profile today, the 30-year-old star wrote: "It is with heavy hearts that Chad and I announce our separation today. Through not only the marriage, but the music as well, we've created many unforgettable moments.
"We are still, and forever will be, the best of friends, and will always care deeply for each other. To all our family, friends and fans, thank you sincerely for the support."
The blonde beauty also posted a smiling snapshot with her estranged husband, 40.
The former couple, who got married in the South of France in July 2013, first sparked rumours they were on the verge of splitting last September after Chad skipped Avril's 30th birthday party in Las Vegas.
An insider claimed at the time: "It's over. He has been going around LA telling people that they are divorcing."
But Chad later claimed he was relieved when Avril, who split from Sum 41 rocker Deryck Whibley in 2010 after four years of marriage, finally confirmed she was secretly battling Lyme disease following months of speculation about their marriage.
Speaking in April, he said: "I'm like, 'OK, the wife has come out and said this, and now I don't have to keep hiding.'
"With everyone going 'What's wrong with your wife? What's wrong with your wife?' and me just going, 'Ah, she's gonna be fine.'
"I'm like 'OK, I can talk about this now.'
"Things are looking up and definitely getting better."