The 31-year-old actress stopped by The Talk on Wednesday and couldn't help but praise the sweet way her fiance asked for her hand in marriage. The couple have been together since 2017 and Koma, a 32-year-old singer-songwriter, popped the question last month.
"I came home from work on a random Tuesday. And he's like, let's go for walk, let's go check out this park," Duff recalled. "And we were living in Williamsburg, and I was like, 'I'm so tired.' We just started Game of Thrones and I'm like, 'I want to eat dinner in bed and watch Game of Thrones. And he's like, 'No, no. Let's go on a walk.' And I'm like, 'Ugh. If I put my sweatpants on I'll go.' And he's like, 'OK.'"
"So, we go, we find this gorgeous park, and he presents me with this book that he said he's been working on for a while. And he's like, 'It's our story,'" she continued. "And he had this amazing guy, Shane, do all these illustrations. And he was like, '... We're going to forget things along the way, so we need to constantly fill this out, so our kids can know our story.'"
When Duff reached the end of the precious present, she peeled open a compartment where she found her stunning ring.
"It was so sweet. It was so sweet," she said. "And he got down on one knee and he's like, 'I forgot everything I'm supposed to say, but you're my best friend.' It was so sweet."
Duff and Koma initially shared the happy news on Instagram with matching pics. In one shot, a giddy Duff is showing off her new bling while Koma can't stop smiling next to her. The other photo shows the pair kissing in the park where they got engaged.
"I asked my best friend to marry me... @hilaryduff," Koma captioned his post.
"He asked me to be his wife♥️," Duff wrote alongside her pics.
Shortly after, Duff shared a pic of herself holding her and Koma's daughter, 7-month-old Banks. Both she and Banks are smiling and giggling in the black-and-white shot, which Duff captioned, "told Banksy the news✨."
When ET spoke to Duff in January she said the two were not rushing to get married.
"I'm really happy, he's amazing, and I mean, honestly, we don't really want to leave the house that much these days," she admitted. "We just stare at our baby and we're like, 'Look what we made. We did this.' And he's such an amazing dad and so supportive and I just feel very happy."