Charlene, 36, and her husband each cradled a child as they stood before the delighted public, smiling and waving as they looked down on a sea of red and white flags, banners and balloons. The month-old babies were both swaddled in white blankets, and appeared to sleep throughout the event.
Albert emerged carrying his son while Charlene took charge of their daughter. The couple interchanged the babies part-way through the presentation.
It was the first of many public appearances for the royal babies, who were born on 10 December at the Princess Grace Hospital – the hospital named after their grandmother.
Wednesday had been declared a public holiday, and there was an overwhelming sense of celebration and excitement as more than 3,000 residents gathered below the balcony for their first sighting of the twins.
Preparations for the occasion had begun one day earlier, as the streets and buildings in the principality were adorned with flags and messages of congratulations for Albert and Charlene.
Two weeks after the twins' arrival, the world was given its very first glimpse of Gabriella and Jacques in a series of images released on the official palace Facebook page.
The children are the first royal heirs born in Monaco since the birth of their father 56 years ago – and Monaco celebrated their birth in a style befitting the historical event. Church bells rang out for 15 minutes, and there were 21 cannon shots fired for each twin as news of their arrival was announced.
Gabriella was the first to arrive on 10 December, at 5:04pm, with her brother following two minutes later at 5:06pm.
According to Monaco's inheritance law, which favour males, Jacques will one day become the ruler of Monaco, and will be known as His Serene Highness The Hereditary Prince of Monaco, Marquis of Baux. Gabriella has the title of Her Serene Highness The Countess of Carladès.