Newly-engaged Princess Alexandra of Hanover dazzles in a gold Givenchy gown once worn by her late grandmother Grace Kelly

She announced her engagement to her long-term partner ten days ago, and now, Princess Alexandra of Hanover has given fans another dazzling update.The granddaughter of Oscar winner Grace Kelly took to her Instagram account to share her latest glamorous ensemble with her 49,000 followers.'Yellow mood in archival Givenchy,' wrote Princess Caroline of Monaco's Ernst August, Prince of Hanover daughter.To the delight of royal fans the world over, Alexandra, 27, opted for a gown once worn by her actress grandmother Princess Grace, the wife of Prince Rainier of Monaco.The shimmering floor-length dress, featuring dainty straps and a round neckline, boasts a daring low-cut back and was worn by the High Society star in 1962 to the pre-wedding gala of King Juan Carlos and Queen Sofia of Spain.It's unclear what glamorous occasion Alexandra was attending over the weekend, but fans and friends alike rushed to compliment her on her ensemble.Close pal and the wife of F1 driver Charles Leclerc, Alexandra Leclerc, commented three heart-eyes emojis under the royal's post.Alexandra's outing comes after she announced her engagement to her long-term partner, Ben-Sylvester Strautmann. She announced her engagement to her long-term partner ten days ago, and now, Princess Alexandra of Hanover (pictured) has given fans another dazzling update To the delight of royal fans the world over, Alexandra, 27, opted for a gown once worn by her actress grandmother Princess Grace, the wife of Prince Rainier of Monaco (pictured next to each other)The happy couple, who have been together for 10 years, shared the news on September 11 in a series of loved-up snaps posted to the royal's personal Instagram account.Alexandra showcased her sparkling 18-carat yellow and white gold diamond ring in a smiling photo with her German partner. In images captioned 'The marriage plot,' Alexandra gave her followers an intimate glance into her special moment. She posed beside her beloved dachshund, Eloise, with her left hand strategically on show, displaying the dazzling ring, which was designed by Antinori di Sanpietro.She also flashed her new jewel in a picture of a tasteful breakfast spread, and in its box on what appeared to be a bedside cabinet. The ring - specially picked by Mr Strautmann - incorporates elements inspired by the design of the Piazza del Campidoglio in Rome, and inscriptions including 'Antinori' and 'Made in Italy,' referencing the couple's love for the city.The royal, whose grandmother is the late American actress-turned Princess of Monaco Grace Kelly, received messages of congratulations from royals and celebrities alike who penned their delight on her social media page. Princess Maria-Olympia of Greece, 30, expressed her joy at the news, writing: 'Omgggg congratulations!!!' followed by emoticons including a sparkle and heart. The granddaughter of Oscar winner Grace Kelly took to her Instagram account to share her latest glamorous ensemble with her 49,000 followers 'Yellow mood in archival Givenchy,' wrote Princess Caroline of Monaco's Ernst August, Prince of Hanover daughter Princess Alexandra announced her engagement to her long-term partner, Ben-Sylvester Strautmann, earlier this monthLady Kitty Spencer, Princess Diana's niece, replied: 'Aah congratulations,' with a string of red love hearts; while influencer and wife of Monégasque racing driver Charles Leclerc, Alexandra Leclerc, said: 'Congratulations!!!!' and added four heart emojis. Princess Alexandra and Mr Strautmann made their relationship official in 2017 after they were first publicly spotted together in late 2016.German-born Mr Strautmann relocated to Monaco as a child where he became a professional basketball player. He now works in finance.The princess is the only daughter of Princess Caroline and Prince Ernst August and is currently 13th in line to the Monégasque throne.She was born in Vöcklabruck, Upper Austria, and boasted a distant claim to the British throne until September 2018, when she was removed from the line of succession after she converted to Catholicism. Now a writer, the princess was formerly an accomplished junior figure skater and even represented her country at the European Youth Olympics. She and Mr Strautmann are well-established members of Monaco's social scene, spotted at events including the Bal D'Ete At The Musée Des Arts Décoratifs in Paris. The pair have also joined the Princess's uncle and aunt, Prince Albert and Charlene of Monaco, as guests of honour at the Principality's many gala balls.