Credit: ChinaFotoPress/ChinaFotoPress via Getty Images

Avril Lavigne and Chad Kroeger separated in September after two years of marriage, but Lavigne revealed Sunday that they were still working together on music.

“YeeHaw! Writing with Chad today,” she wrote on Instagram, before posting a photo of Kroeger with the caption, “Back where it all started…”

The couple also announced their plans to split via Instagram. “Through not only the marriage, but the music as well, we’ve created many unforgettable moments,” Lavigne wrote last month.

In 2013, they released “Let Me Go” together, which was the third single off her album, Avril Lavigne.