Robert Downey Jr. Picture: Instagram

Robert Downey Jr. has teased that he's getting ready to shoot 'Sherlock Holmes 3' after practising his "Sherlock face."

The 53-year-old actor has hinted that he's about to reprise his role as the suave private detective in the third instalment of the adventure mystery film after he took to his social networking sites to "practice" his "Sherlock face" ahead of production.

Alongside a gif of him in character, he wrote: "Practicing my Sherlock face."

Warner Bros. and Village Roadshow Pictures have confirmed that the mystery period action film will hit the big screen on December 25 two years from now - nine years after the first sequel 'Sherlock Holmes: A Game of Shadows' dropped worldwide. 

Jude Law - who starred in the first and second film - will reprise his role as Dr Watson alongside Downey Jr's Sherlock, while the rest of the cast is yet to be announced. 

The third instalment will be based on a script penned by Chris Brancato, while Susan Downey, Joel Silver and Lionel Wigram are on board to produce, Empire reports.

However, bosses are yet to secure a director - meaning Guy Ritchie, who directed the first two films, may have turned down the third movie or is yet to sign a contract. 

'Sherlock Holmes' was released on December 25, 2009, and earned $524 million globally, while the second flick 'A Game of Shadows' debuted in December 2011 and earnt $545.4 million at the worldwide box office. 

Although fans are no doubt looking forward to seeing Downey Jr. slip back into his high-collared jacket with his slicked back hair, the festive season in 2020 looks set to be a busy one and somewhat competitive as James Cameron's long-awaited 'Avatar' sequel is scheduled to open on December 18, followed by 'Sing 2' on Christmas Day.