Princess Charlene of Monaco left fans divided with her greeting for King Felipe VI of Spain during a historic meeting in Madrid yesterday.On Monday, Charlene, 48, and her husband, Prince Albert, were welcomed by Felipe and Queen Letizia at the Palace of Zarzuela in the Spanish capital for their first ever official visit.Marking a significant diplomatic milestone for the Monegasque royal couple - all eyes were on the group as they began a tour of the city's Royal Botanical Garden.Yet eagle-eyed onlookers suggested that Charlene may have made an unfortunate protocol breach during the poignant meeting - by curtsying to both Felipe and Letizia. 'Princess Charlene's protocol error: Although the title is that of Princess, she is the consort of a head of state, therefore, she should not curtsy to the Kings,' noted one X user.Meanwhile, another Instagram commenter criticised the royal for 'making an absolutely incorrect curtsy' and leaving members of the public 'perplexed'. However, others online came to Charlene's defence and suggested that it was not in fact a protocol error, and that the 'perfect' princess had indeed been acting in line with royal etiquette. 'it is not the same to be "His/Her Serene Highness" as it is to be "Majesty", it's a higher rank,' wrote one user, while another added: 'They are neither royal highnesses; therefore, Charlene's reverence is perfect'. Princess Charlene of Monaco has divided fans with her greeting for King Felipe VI of Spain during a historic meeting in Madrid yesterday On Monday, Charlene, 48, and her husband, Prince Albert, were welcomed by Felipe and Queen Letizia at the Palace of Zarzuela in the Spanish capital for their first ever official visit Eagle-eyed onlookers suggested that Charlene may have made an unfortunate protocol breach during the poignant meeting - by curtsying to both Felipe and LetiziaWhile Charlene's alleged protocol breach remains widely disputed, the event is not the first time the royal has been criticised for going against traditional etiquette and formalities. Indeed, in 2019, Charlene herself admitted that she struggles to keep up with the abundance of protocol rules and restrictions - and often finds it confusing. Speaking candidly about the realities of royal life, she confessed to Rapport in 2019: 'I address royals incorrectly, or often curtsey to those I shouldn't be curtsying to, or I forget to curtsy'. However, while some may have perceived Charlene's curtsy as a faux pas, the first day of her and Albert's two-day Spanish visit was said to have gone incredibly well - and helped to strengthen ties between the two nations.The possible protocol breach comes just days after the royal household shared an unseen photograph of Charlene with her arms wrapped around her 11-year-old twins, Princess Gabriella and Prince Jacques. Captioned 'wishing all moms a Happy Mother's Day', the image offered a rare insight into the lives of the two young royals, who are largely kept out of the spotlight despite being members of the Monegasque royal family.Coordinating for the special occasion, Charlene was dressed in an off-white jumper, while Jacques opted for a white crew-neck and Gabriella showcased a sparkly white dress.Images from the same photo shoot were previously released on December 10 in honour of the royal twins' 11th birthdays, with adorable portraits showing the youngsters looking the spitting image of their former Olympian mother. However, others online came to Charlene's defence and suggested that 'it is not the same to be "His/Her Serene Highness" as it is to be "Majesty", it's a higher rank' The first day of Charlene and Albert's two-day Spanish visit was said to have gone incredibly well - and helped to strengthen ties between the two nationsWhile Gabriella is slightly older, being born mere minutes before her brother, Jacques is the first heir to the throne due to male-preference succession.Jacques holds the title of Marquis of Baux, while Gabriella is the Countess of Carladès, honours given to them upon birth by their father, Prince Albert, 68, who married former Olympic swimmer Charlene.The royal twins look distinctly more grown-up in their official portraits compared to the series of candid snaps posted for their 10th birthday last year.In 2019, Princess Charlene gave a rare insight into family life with her two young twins and described how her 'smart' daughter Gabriella bounces out of bed to go to school on a Saturday - and is left disappointed when it's closed.She said they feel 'blessed' to have two children who fill them with 'love and happiness', and are also 'well behaved and kind'.She told French magazine, Point de Vue, according to People, that they also take time to remember those less fortunate in their prayers every night.'They know what they want, they speak very well and understand many things. It’s hard to believe they’re already four,' the former Olympic swimmer explained.In recent months, Jacques and Gabriella have made more public appearances, and in March were present during Pope Leo XIV's historic visit to Monaco.Gabriella, who bore a striking resemblance to her mother, were joined by Jacques and Prince Albert for the occasion, which saw Pope Leo make his first visit to the European country since his election in May.Both Charlene and Gabriella wore white in line with the so-called 'privilege of the white' - a rare exception to the historic dress code that permits only queens and princesses from Catholic countries to wear white when meeting with the Pope.They are each one of only seven women in the world who have the rare ability to wear white when meeting with the Pope.Called le privilége du blanc in French or il privilegio del bianco in Italian, the special tradition is extended solely to designated Catholic queens and princesses and is reserved for important events such as private audiences, canonisations, beatifications and special masses.Normal protocol for papal audiences requires that ladies wear a long black dress with a high collar and long sleeves, and a black mantilla.For the outing, Charlene, 48, also donned a small brooch with the flags of Monaco and the Vatican, alongside a midi dress that contained lace detailing and a short veil, which she placed over her head in line with the necessary protocol.While her mother opted for white heels, 11-year-old Gabriella wore white ballet flats, alongside a long coat and the same brooch as her mother.