Royals James Middleton 'Couldn't Be Happier' About Engagement to Alizee Thevenet as She Debuts Sapphire Ring "She said OUI," James Middleton wrote alongside a smiling photo of the couple, which also showed off Alizee Thevenet's stunning engagement ring By Maria Pasquini Maria Pasquini Maria Pasquini is the staff editor for human interest’s digital vertical at PEOPLE. She has been working at PEOPLE since 2017. People Editorial Guidelines Published on October 6, 2019 12:00PM EDT James Middleton and Alizee Thevenet are over the moon about their engagement! On Sunday, one day after news of their engagement first broke, Kate Middleton’s younger brother confirmed the couple’s happy news. “❤️She said OUI ❤️,” he wrote alongside a smiling photo of the pair, which was taken after James, 32, proposed to the French financial analyst based in London. “Our secret is out but we couldn’t be happier to share the news,” he wrote, adding a sweet hashtag with their couple nickname, Jalizee, as well as some celebratory emojis. In the selfie, which was taken in England’s Lake District, the pair have huge smiles on their faces, as Thevenet lovingly places her hand on James’ chest. The sweet display of affection also shows off her stunning engagement ring, which appears to consist of a sizable sapphire. The jewel could be a nod to the sapphire and diamond engagement ring Prince William gave to Kate back in 2010. James Middleton Is Engaged to Girlfriend Alizee Thevenet: Report James went on to share a handful of affectionate clips of the couple on his Instagram Story. In the first post, the duo shared a playful underwater kiss as they spent time together on the water. “I asked @alizeethevenet a question the other day…” he wrote alongside the clip. A second post, which featured a slideshow of photos taken throughout the course of their relationship, went on to tease the bride-to-be’s answer. “And she said…” he wrote. James Middleton and Alizee Thevenet. James Middleton/Instagram The Daily Mail was the first to report on the couple’s engagement. “They’ve been keeping the engagement secret, but news has started to leak out among their friends,” one of the couple’s friends told the outlet, adding that Thevenet “has been wearing a beautiful sapphire sparkler” on her finger. RELATED VIDEO: All About Princess Beatrice’s Engagement Ring and Why There’s a Meghan Markle Connection Although the couple has kept their romance mostly under wraps, James brought Thevenet along to a family vacation in St. Barts with James’ sister Pippa, 36, and her husband James Matthews in January. The couple was previously seen together in December 2018, when they went to the Henry van Straubenzee Memorial Fund’s Christmas Carol Service at St. Luke’s Church. Over the summer, James also shared a candid photo of his golden retriever Mabel excitedly jumping into the pool as Thevenet sported a red bikini. Can’t get enough of PEOPLE’s Royals coverage? Sign up for our newsletter to get the latest updates on Kate Middleton, Meghan Markle and more! Back in 2018, James’ mother Carole Middleton, opened up about her hopes for her son’s love life with U.K. newspaper The Telegraph, saying she hoped to have a “lovely daughter-in-law” someday. “I’m definitely hands-on. I don’t find it complicated,” Carole said of her approach to motherhood. “My biggest fear [as her children grew up] was that I’d lose my family, but we’ve stayed close. There are times when they say, ‘Can you do this, or that?’ And I can’t quite. But they like the fact that I work. I have two lovely sons-in-law, and I hope I’ll have a lovely daughter-in-law.”