Roger Federer and Serena Williams have been named as the 2009 world champions by the International Tennis Federation.
Federer claims the honour for the fifth time, while Williams wins it for the second.
The award caps a memorable year for Federer, who won the French Open and Wimbledon titles - completing a career Grand Slam and surpassing Pete Sampras' record of Grand Slam singles titles in the process.
The Swiss, who was also runner-up at the Australian and US Opens, said: "It is an honour for me to be named ITF world champion for a fifth time."
"It was an incredible year for me both on and off the court. To win my first Roland Garros title, break the all-time Grand Slam record and regain the No.1 ranking is amazing. It means a lot to me to finish the year again at the top."
Meanwhile, women's world No.1 Williams adds the title to the one she claimed in 2002.
She won the Australian Open and Wimbledon crowns during the year, as well capturing the season-ending Sony Ericsson Championships in Qatar.
In fact there was double delight for Williams who was also named as world doubles champion, alongside her sister, Venus.
The siblings won three of the four Grand Slam titles in 2009, missing out only at the French Open, taking their career total to 10 Grand Slam doubles triumphs
Serena becomes the first player since Martina Hingis in 1999 to win both the singles and doubles world champion awards.
American twins Bob and Mike Bryan were named men's doubles world champions for a record sixth time, while Swede Daniel Berta and France's Kristina Mladenovic claimed the junior awards.
ITF president Francesco Ricci Bitti said: "This has been another memorable year for tennis, with some outstanding performances by our world champions. Roger Federer has truly earned his place in the history books, while the Williams sisters remain the strongest competitors on the women's tour."
The awards will be handed out at the ITF Word Champions Dinner, which takes place in Paris on June 1 during the French Open.