The couple and Stewart live right around the corner from each other in New York and have become good friends. Blake and Ryan wed at Boone Hall Plantation in Mt. Pleasant, South Carolina, on Sept. 9 and Stewart helped organize their special day.
Stewart told Life & Style magazine, "They're good friends of mine who live around the corner from me, so we got involved that way because it's through friendship.
"Our wedding team helped Blake orchestrate the event, and they did a phenomenal job. Nobody does it better than our weddings team!"
Photos from Blake and Ryan's wedding will be included in the December issue of Martha Stewart Weddings.
Lively wore a stunning Marchesa ball gown with a hand-draped silk tulle bodice with crystal and rose gold embroidery and carried a bouquet of white and peach roses, peonies, and hellebores. Her hair mostly down, she went without a veil and was accompanied by bridesmaids in blush silk chiffon Marchesa gowns with crystal embroidery.
The wedding was an intimate affair with approximately 60 guests. Blake's co-stars from "The Sisterhood of the Traveling Pants" attended, including America Ferrera, Amber Tamblyn, and Alexis Bledel. A reception was held under a white tent at the plantation, and British rocker Florence Welch, a close friend of Blake's, performed at the party.