COPENHAGEN, Denmark — Prince Joachim, the youngest son of Queen Margrethe of Denmark, has undergone emergency surgery for a blood clot in his brain, the royal palace said.

The 51-year-old prince, who had been on vacation in France, was admitted to the Toulouse University Hospital late on Friday and was immediately operated on. The palace said he is in a stable condition and that his French-born wife is by his side.

Joachim married Marie Cavallier, with whom he has two children, in 2008, and she became Princess Marie. He also has two children from his first marriage to Hong-Kong born Alexandra Manley, who became Countess of Frederiksborg after their divorce in 2005, the first split in nearly 160 years in Europe's oldest monarchy.

Earlier this month, he was all smiles at the Danish queen's summer residence in France, Chateau de Cayx, when he posed for a photo in connection with his oldest son's 18th birthday.

Joachim is sixth in the line to Denmark's throne after his elder brother, Crown Prince Frederik, and his brother's four children.