The actor shared a series of unseen photos, including one that showed the family in The Wizard of Oz-themed fancy dress, along with a video of Jennifer saying she hoped to be home by bedtime.
WATCH: Jennifer Garner shows off impressive kitchen and living room
Ben, 48, wrote: "So happy to share these kids with you. Luckiest parents in the world. Thanks for all the good you do. Happy Mother's Day. Love, their dad."
Ben and Jennifer were married from 2005 until 2018 and are the proud parents of Violet, 15, Seraphina, 12, and nine-year-old Samuel.
Ben Affleck shared a sweet message for ex-wife Jennifer on Mother's Day
They have remained on good terms following their divorce, with 49-year-old Jennifer previously telling Vanity Fair: "The main thing is these kids – and we're completely in line with what we hope for them.
"Sure, I lost the dream of dancing with my husband at my daughter's wedding. But you should see their faces when he walks through the door. And if you see your kids love someone so purely and wholly, then you're going to be friends with that person."
The former couple share three children together
Ben, meanwhile, opened up to The New York Times in February 2020 about his divorce, admitting that the breakdown of his marriage was the "biggest regret" of his life.
The talented actor said: "The biggest regret of my life is this divorce. Shame is really toxic. There is no positive by-product of shame. It's just stewing in a toxic, hideous feeling of low self-worth and self-loathing."
Jennifer and Ben were married from 2005 until 2018
In recent weeks, Jennifer has found herself at the centre of new romance rumours. Multiple reports claim that she has rekindled her relationship with John C. Miller after some time apart.
Jennifer and John – CEO of Caligroup – first started dating in mid-2018 but by August 2020 were said to have ended their romance.
The pair never confirmed their relationship, nor their split, but they were pictured together out in public on a number of occasions.
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