She might be celebrating her 75th birthday today, but an overjoyed Queen Margrethe of Denmark looked far younger as she waved to excited crowds from the balcony at the Amalienborg Palace. The Danish monarch was joined for the balcony appearance by her son and heir, Crown Prince Frederik, 46, his wife Crown Princess Mary, 43, and their four children. Waiting below was an enormous flag-waving crowd who went into raptures as the royals appeared, watched by members of other European royal dynasties, among them Sweden's and Norway's. Scroll down for video . Royal wave: Queen Margrethe is flanked by her sons Frederik and Joachim as she waves to the crowds . Celebrating: Denmark's Crown Prince Frederik, his wife Mary and their nine-year-old son Prince Christian on the balcony . Family affair: Frederik and Mary were joined by their four children, including twins Vincent and Josephine . Pay attention! Four-year-old Vincent appeared more interested in scaling the balcony rails . What's going on? Prince Christian grimaces at something in the crowd during his grandmother's birthday celebrations . Also on the balcony was Margrethe's second son, Joachim, 45, his French wife Princess Marie, his children from his first marriage, Nikolai, 15, and Felix, 12, and his youngest two, Henrik, five, Athena, three. One royal who couldn't be present on the balcony or for the lunch at the Københavns Rådhus [City Hall] that followed was Margrethe's 80-year-old husband Prince Henrik who, according to palace officials, is suffering from flu. The French-born royal also missed the carriage procession down Copenhagen shopping street Strøget to the Rådhus and was replaced for the day by his son Frederik. Despite being without Prince Henrik, the appearance proved a cheerful affair - largely thanks to the antics of four-year-old Prince Vincent, who did his best to scale the railings of the balcony. Held back by his father, the youngster smiled mischievously and was quickly copied by his twin sister Josephine - much to their mother Princess Mary's amusement. Girls together: Prince Joachim holds his three-year-old daughter Athena, while Crown Princess Mary clutches four-year-old Josephine . Overjoyed: Queen Margrethe, who was without her husband Prince Henrik, appeared overcome . Saying thank you: Margrethe, who was resplendent in a turquoise ensemble, waved to the crowds . Saying hello: The Danish royals toured Copenhagen following the balcony appearance . Enjoying the day: Denmark's Princess Marie, Crown Princess Mary and Queen Margrethe wave to the crowds outside the Amalienborg Palace . Enjoying the ride: Margrethe and Mary sat opposite each other during the procession along Strøget . Pomp: The royals were followed down main shopping street Strøget by a detachment of guards . Birthday wishes: Queen Margrethe enjoyed an official luncheon at the Københavns Rådhus at the end of the procession along Strøget . Joining in: Swedish royals, including Crown Princess Victoria, also appeared on the balcony . Showing their support: Sweden's 65-year-old King Carl XVI Gustaf and his Brazilian-born wife, Queen Silvia . Support: Norway's Crown Prince Haakon, Crown Princess Mette-Marit and King Harald on the balcony . Enjoying the moment: Deposed King Constantine II of Greece, his wife Queen Anne-Marie and Princess Benedickte of Denmark on the balcony . Australian-born Mary, who was elegant in a navy ensemble topped with a grey cocktail hat, certainly appeared to be enjoying the moment, smiling broadly as she stood with her four children. Frederik, meanwhile, was content to wave to the crowd and at one point leaned down to whisper in the ear of his older son, nine-year-old Prince Christian. The moment came on the second day of Margrethe's birthday celebrations which began last night with a gala dinner at the Christiansborg Palace and continued with a procession this morning. Among the guests to join the Danish contingent for the event were crowned heads from the Netherlands, Belgium, Spain and Luxembourg as well as those from Sweden and Norway. Spain's King Felipe and Queen Letizia, the youngest reigning royals in Europe, led the way in, followed by the equally glamorous King Willem-Alexander and Queen Maxima of the Netherlands. Norway's King Harald, who joined the Danish royals on the balcony today, was accompanied by his wife Queen Sonia, and his son Crown Prince Haakon and daughter-in-law Mette Marit. Sweden's 65-year-old King Carl XIV Gustaf also brought his heir, in his case Crown Princess Victoria, 38, and her former personal trainer husband, Prince Daniel. Other royals to attend included the elegant Queen Mathilde of the Belgians who shimmered in a stunning purple gown at last night's event and smiled broadly as she made her way inside on the arm of husband King Philippe. Watch out for the wind! Norway's Crown Princess Mette-Marit, 41, and Sweden's Crown Princess Victoria, 37, attended the event . Future queen: Crown Princess Victoria chats to her husband and former personal trainer Prince Daniel, 41, during the celebration . Outpouring: Thousands gathered outside the Amalienborg Palace and along Strøget . Overjoyed faces: Flag-waving crowds snapped pics outside the Amalienborg Palace . Crowd control: Thousands of revellers patiently awaited for the royals to come out on the balcony . Denmark's official royal magazine, Billed Bladet, celebrates Margrethe's 75th birthday by featuring the queen on the cover . Joyful: The crowds were particularly delighted when Queen Margrethe appeared on the balcony . Wake up: Crown Prince Frederik and Crown Princess Mary prepare to wake Queen Margrethe . Friendly: Crown Princess Mary with Queen Maxima (left) and Crown Prince Frederik with nephew Nikolai . Windy: The chilly Danish weather appeared to be taking its toll on Crown Princess Mary's hair . Getting better: Queen Mathilde, who recently injured her knee, showed off a black knee-brace . All smiles: The Belgian royals and Grand Duc Henri of Luxembourg also took part in the wake-up . Excited: Prince Joachim's youngest son Henrik, five, (in blue coat) looked thrilled to be taking part . Delighted: Queen Margrethe looked pleased with her wake-up and smiled broadly at her family . Hello there! She then leaned down to wave at the gathering below . The former ruler of Greece, King Constantine II, 74, also attended, as did his wife Queen Anne-Marie who was ravishing in her emeralds. Politicians were also among the guests last night, with Denmark's glamorous prime minister Helle Thorning-Schmidt giving the royals a run for their money in a shimmering cream tulle gown. Iceland, a colony of Denmark for more than 600 years, was also represented, with President Ólafur Ragnar Grímsson attending with his Israeli wife, Dorrit Moussaieff. Several speeches were made during the dinner, including a tribute from Crown Prince Frederik which the 46-year-old made in three different languages. The Danish heir was also among the party that arrived at the Amalienborg Palace early this morning to help Queen Margrethe get her birthday off to a wonderful start. Joined by the Netherlands' Maxima and Willem-Alexander as well as all of the Danish royal children, Frederik serenaded his mother with a chorus of a traditional Danish folk song from beneath her window. A clearly delighted Margrethe was seen peering out in surprise before smiling broadly and offering the singers a round of applause. Speech! Crown Prince Frederik paid tribute to his mother in three languages last night . Guests: King Philippe and Queen Mathilde of the Belgians and King Felipe and Queen Letizia of Spain . Chat: Grand Duc Henri of Luxembourg chats to Crown Princess Mary during the dinner . Celebrating: Joachim and Marie of Denmark and Willem-Alexander and Maxima of the Netherlands . Glamorous gathering: The scene in the banqueting room at the Christiansborg Palace last night .
Queen Margrethe II of Denmark is celebrating her 75th birthday today and appeared on the palace balcony . Was joined by Crown Prince Frederik, 46, and Crown Princess Mary, 43, as husband Henrik is ill with flu . Started birthday celebrations with a glitzy gala dinner last night attended by royals from around Europe . No members of the British royal family were able to attend the glitzy celebration in Copenhagen .