The former Culture Secretary joined David to play a leading role in delivering the London 2012 Olympics. She died from a brain tumour in 2018.
The Tessa Jowell Foundation is organising the release of a film of the 2012 opening ceremony to be screened in cinemas across the country, with the proceeds going to the foundation.
The group is hoping to raise £4million for brain cancer care.
David said: “Brain cancer is the biggest cancer killer of children and people under 40 in the UK.”
“As a close friend of Tessa, it is my honour to help support her family foundation to deliver her final campaign – to transform NHS brain cancer care in Britain.”