His Majesty the King loves sports and has been a patron of several sporting events and associations.
When he was younger he played several sports including badminton and tennis, and was Thailand's top sailor in the 1960s.
His Majesty is the first Thai monarch to have competed in an international sporting event when he took part in sailing at the Southeast Asian Peninsular (SEAP) Games (now the SEA Games) in 1967.
The King won gold in the OK dinghy class and the achievement was more remarkable because he built his own boat.
He claimed the title on Dec 16 which has since been Thailand's National Sports Day.
The International Olympic Committee (IOC) awarded him the Insignia of the Olympic Order in 1987 and presented him with the Lalounis Cup in 2001 for his leading role in supporting and promoting sports.
In 2012, the King received the President's Medal from the Badminton World Federation for his contribution to the sport.
"All sports must be played according to the rules," the King once said.
On another occasion, he said: "Sports are important in the development of the country and people."
The King has always encouraged athletes to put the sporting spirit first, and strive for victory and friendship."
Because of His Majesty's involvement in sports, several sporting events will be held today to mark the King's 87th birthday.
In football, the Global Legends Series (GLS) will kick off today at SCG Stadium in honour of the King.
More than 30 former stars will play in the event including Fabio Cannavaro, Luis Figo, Patrick Kluivert, Andriy Shevchenko, Christian Karembeu, Clarence Seedolf, Michel Salgado, Cafu and Davor Suker.
The players are divided into two teams which will play against each other with Italy's 2006 World Cup captain Cannavaro leading one side and Portugal's Figo captaining the other.
The other players include Marco Materazzi, Jari Litmanen, Hidetoshi Nakata, Steve McManaman, Paul Scholes, Michael Owen, Alexandro Nesta, and Karl-Heinz Riedle.
Two Thai players, Therdsak Chaiman and Datsakorn Thonglao, will also feature in today's match.
Before the match, which is scheduled to kick off at 7.30pm, there will be a candle lighting ceremony to celebrate His Majesty's birthday.
"I am glad and proud to be part of the celebration and Thai history,'' said Suker, the highest scorer at the 1998 World Cup and now president of the Croatian Football Federation.
Organiser Bee Taechaubol said: "It is an opportunity to create an inspiration for young Thai players and for the players to honour His Majesty the King.''
Former referee Howard Webb will officiate the match.
The Badminton Thai Glory to King will be held at Indoor Stadium, Hua Mark, beginning at 1pm.
World No.4 Ahmad Tontowi and Natsir Liliyana of Indonesia, last year's world champions will meet Kunchala Voravichitchaikul and Songphol Anugrityawon in a mixed doubles match.
In the men's doubles, Bodin Issara and Pakkawat Vilailak will take on Indonesia's Hendra Setianwan and Mahammad Ahsan, ranked second in the world.
Boonsak Ponsana is expected to play China's Lin Dan, who was originally scheduled to play long-time rival Lee Chong Wei of Malaysia.
However, world No.1 Lee is serving a provisional suspension for doping, pending a final decision by the Badminton World Federation (BWF), and cannot play.
Although the BWF has said that Lee, 32, can demonstrate his technical skills but the player has decided not to do so to avoid further problems and will only make his appearance at the event, according to the organisers.
"We accept Lee's decision and understand his case,'' said organising committee chairman Jane Piyatat.
Ticket holders for the event will get refunds, he said.
At Sanam Luang, a Muay Thai event, featuring local and international fighters, will begin at 6pm and last until late in the night.
The Phuket King's Cup Regatta will end today and participants will take part in a ceremony to mark the King's birthday.
The competition was launched in 1987 to celebrate His Majesty's 60th birthday and has been held every year since, during the first week of December.
Under royal patronage, the Phuket King's Cup Regatta is one of Asia's most prestigious sailing tournaments.