Ann Marie O'Sullivan is a Cork writer and freelance journalist who self-published her debut children's book, Pimlicat and the Midnight Explorers, in 2024—an adventure set in London's Underground, which she wrote and illustrated herself after being inspired by a family trip. She previously worked in policy and legal administration for New Zealand's Ministry of Justice and in disability advocacy in Ireland.

The book was followed in 2025 by a sequel, Trapped at the Science Museum.

After a breast cancer diagnosis during the pandemic, she has since recovered and now volunteers with Fighting Words Ireland and Dragon Boats, while also facilitating creative writing workshops for young people in Cork.