The estranged married couple, who announced their split last month, seem to be on friendly terms as the 'Hello Kitty' singer posted pictures of her and the Nickelback star in the studio together.
Avril posted a picture of Chad holding a guitar on her Instagram and wrote: ''Back where it all started ... (sic)''
She captioned another picture: ''YeeHaw! Writing with Chad today (sic)''
The 31-year-old singer appears to have maintained a good relationship with her former husband, following her announcement the pair have split but plan to remain ''the best of friends''.
Announcing their separation on September 2, Avril wrote in a statement: ''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.''
Avril and Chad got married in a French castle in July 2013, but rumours about their marriage being on the rocks began spreading in 2014.
It was recently claimed the pair didn't ''see eye to eye''.
A source said: ''Honestly, she's doing OK. This has been in the works for awhile.
''Chad is being supportive. At the end of the day, they just didn't see eye to eye on a lot of things.''
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