The Good Will Hunting star honoured his actress wife Jennifer Garner, with whom he shares three children, his mum Chris and all the mothers across the globe with a Facebook.com video message, which he filmed during a recent trip to the war-torn Democratic Republic of Congo (DRC).
In the clip, he says, "I want to say Happy Mother's Day to all the mums in my life - my mum, Chris, and my amazing wife, Jennifer, who is an incredible, spectacular, world-class mum. Please share this video for the mothers and grandmothers in your lives in honour of their sacrifices, selflessness and courage."
The emotional tribute, which also features images of mums and their children in the poverty-stricken African country, also urges fans to not just remember their own mothers on Sunday, but also those in other parts of the world.
He continues, "I want to say Happy Mother's Day to all the mums I've met in the Democratic Republic of Congo who are on this video that I hope you watch. I urge you to share it, to post it to Facebook, to celebrate all the mums in the world, including the ones in your life, as well as those out there in the world working at the very hardest job there is every single day."
Affleck and Garner are parents to Violet, six, Serafina, three, and baby Samuel, who was born in February (12).
The 39 year old has been very active in the DRC - he founded the humanitarian organisation Eastern Congo Initiative in 2009 and he's currently making a film about the plight of the nation's people.