The 64-year-old King Vajiralongkorn is the second of four children of late King Bhumibol Adulyadej and Queen Sirikit. He is their only son.

Vajiralongkorn studied in the United Kingdom and Australia. He served in the Thai military as a pilot, and earned recognition for his role in fighting insurgents in the 1970s.

He also holds high ranks in the Thai army and navy.

He's visited China four times.

In this photo provided by the Thai Royal Household Bureau, Crown Prince Maha Vajiralongkorn attends a succession ceremony to become King Rama X in Bangkok, Thailand, on Dec.1, 2016. Thailand's Crown Prince Maha Vajiralongkorn accepted invitation from parliament president to ascend to the throne and thus formally proclaimed King Rama X in a televised ceremony broadcast late Thursday. (Xinhua/POOL/Thai Royal Household Bureau)