Miranda Kerr has revealed that when her boyfriend of one year - Snapchat founder Evan Spiegel - proposed in the summer, it came as a complete surprise, reports Vogue on Monday.

"Was I expecting it? Absolutely not. He said to me, 'Miranda, I'm telling you now, this is the first and last time I'm going to kneel down in front of you,'" the model, who announced their engagement on Instagram with a picture of her ring, told Female First. "I was terribly nervous and emotional, trembling with happiness."

I said yes!!! ❤️????❤️????❤️

A photo posted by Miranda (@mirandakerr) on

According to Kerr, the couple will wed next year but she kept quiet about further plans for the nuptials. She did disclose, however, that Spiegel has bonded with her five-year-old son, Flynn - whose father is Kerr's first husband, Orlando Bloom - though she admitted that she was cautious about introducing them.

"They adore each other," she said of her son and fiancé's relationship. "At first I was very careful as I wanted to be certain our relationship was serious. Now I love to watch them playing together."

The former Victoria's Secret Angel had previously revealed to Paris Match magazine that she can turn to Spiegel for advice about anything from work to family.

"We spend hours talking about everything. He listens to me and he understands me. He works very hard and he's proud that I've started my own business. He gives me tons of advice. He's my soulmate."