Yiru Sun was radiant in bridal white Saturday — even though she had called off her wedding at the last minute, instead turning her reception into a feast for the poor.

The pretty Manhattan insurance executive was supposed to tie the knot in a lavish Upper East Side wedding Saturday. But after balking at the proposed prenup, she turned her heartbreak — and her non-refundable $8,000 reception deposit — into something beautiful: a luncheon for 60 needy kids and their families.

“I should have been the bride. It was canceled,” Sun told her guests at the elegant Harold Pratt House at East 68th Street and Park Avenue. “Initially I felt frustrated,” said Sun, a vice president at New York Life Insurance, declining to dish about her former betrothed, not even to name him.

“I don’t want to sign things I don’t feel comfortable with,” is all she’ll reveal of the prenup dust-up.

“Three weeks later, I woke up with this idea,” Sun, herself a single mom of a 6-year-old daughter, told her guests, who were chosen with help from The Salvation Army and Inwood House.

“At that moment, I started to think it was God’s plan,” she said of turning her misfortune into a great party.

“I cannot be the princess of my wedding day, but I can give the kids a fairy tale.”

Sun told her guests at the Pratt mansion that she grew up poor in China but studied hard in America, winning a full scholarship for a graduate degree at Princeton University.

Single moms, and their kids, can face difficulties in life and still do great things, she insisted.

The kids were treated to face-painting and balloons and were touched by Sun’s story, at least as far as they understood it.

“It’s special because this lady canceled a special day for her family and herself just for little kids to have fun,” said Kimberly Gil, 10, who attended with mom Amelia Victorio, 30.

“And she brought ice pops.”