A Waitrose.com sponsored forum on Mumsnet asked users what they would most like their children to cook for them on Mother's Day.
Full-service agency Amp brokered the partnership, which will be ongoing. The agency will also develop a broader range of strategic partnerships to help drive customer acquisition.
Future activity being considered could involve closed forums used to drive proposition development and product testing.
Waitrose.com is also considering using the partnership to get Mumsnet users to test recipes created by Waitrose brand ambassadors Heston Blumenthal and Delia Smith.
Peter Burns, Waitrose.com marketing manager, said: "Mumsnetters are a very engaged and influential audience, many already enjoying the convenience of online grocery shopping in their busy lives.
"Working with Mumsnet is a great way of developing our online proposition and creating really engaging content for parents."
Follow Matthew Chapman at @mattchapmanUK