A Gold Coast lifeguard has saved the life of the 10-year-old heir to the Danish throne.

Prince Christian of Denmark, the eldest son of Princess Mary and Prince Frederick, was plucked from the surf by lifeguard Nick Malcolm while swimming with his family, 7 News Queensland has reported.

The 10-year-old was rescued from the waters of Mermaid Beach on Thursday, after being swept off his feet and out to sea by a strong current.

His Australian-born mother had clearly heeded the message of her childhood, luckily for her first-born.