Queen Mathilde of Belgium, 45, was joined by her husband King Philippe, 58, and their four children Elisabeth, 16, Gabriel, 15, Emmanuel,12, and Eleonore, 10.
Belgian National Day celebrates the separation of the country from the Netherlands.
Mathilde chose a red lace dress with a nude underlay for the event. The dress featured three quarter length sleeves, and came to her knee.
She paired this with an extravagant wide brimmed hat, also red, worn to the side.
Matching her bag to her outfit, the Queen carried a small red clutch bag with a gold clasp.
A pair of red suede court shoes with clear detailing on the sides provided the final red touch.
As befitting her royal status, Mathilde wore a pair of cream gloves.
She added gold touches to the outfit to accessories, wearing a pair of brushed gold earrings and a gold bangle.
Her hair was swept up in to a chic updo, with a side parting hidden underneath her hat.
Mathilde added a pop of colour to her otherwise simple makeup look with a cherry red lipstick.
The Belgian Queen is a fan of vibrant colours, stepping out in a bright yellow dress earlier this month.
She wore the dress while visiting an Art Deco exhibition at the Villa Empain.
She wore a bright yellow dress which had a cut out pattern. A yellow lining could be seen underneath.
To offset the dress, Mathilde chose rose gold accessories – a slim belt and stiletto court shoes.
Despite the warm temperatures, she wore a pair of nude tights.
The Queen matched her outfit with her accessories, wearing a pair of bright yellow hoops and a chunky gold watch.
Villa Empain was a private house built between 1930-1934 by Swiss architect Michel Polak for Baron Louis Empain.
It is now the home of the Boghossian Foundation and is a centre of art and culture, hosting regular exhibitions.
Queen Mathilde is the wife of King Philipe, who become King after his father abdicated in 2013.
Mathilde is the first Belgian-born Queen of Belgium. Born to Jonkheer Patrick d’Udekem d’Acoz, who was of Belgian noble ancestry, and his wife, Countess Anna Maria Komorowska, she grew up on her family’s estate Castle Losange in Villers-la-Bonne-Eau in the Bastogne municipality of Belgium, near the Luxembourgish border.