“My chin is in 3D. I think it's about time,” said Matt. “Frankly I think it's exciting. I think this show was born for 3D. The TARDIS in 3D looks brilliant."
Tickets for 3D showings of the special, which will be screened in 216 cinemas nationwide, sold out in October.
The 75-minute episode stars the current Doctor Matt, his predecessor David Tennant and companions Clara (Jenna Louise Coleman) and Rose (Billie Piper).
Veteran actor John Hurt will also star as a mysterious forgotten incarnation of the Doctor who was born during the Time War – as discovered in the recent online minisode The Night of the Doctor.
The episode is set across different time periods. In 2013, something terrible is awakening in London's National Gallery; in 1562, a murderous plot is afoot in Elizabethan England; and somewhere in space an ancient battle reaches its devastating conclusion.
The show will feature enemies including Daleks and 1975 fan favourite the Zygons, but the Doctor’s own dark past also poses a threat.
The long-running sci fi series will be broadcast simultaneously on BBC1 and channels across the globe, while 20,000 fans will gather at London's ExCel for an official celebration event, featuring appearances from Matt Smith, and former Doctors Colin Baker, Sylvester McCoy and the irreplaceable Tom Baker.
Despite fans’ feverish speculation there are bound to be many surprises in store. As lead writer and executive producer Steven Moffat said, “Most things that have been said about the 50th are not true... Normally I am responsible for the disinformation and the rubbish rumours - I usually put them out myself, but I haven't needed to for this one."
The Day of the Doctor will air on BBC1, in cinemas and 75 countries worldwide at 7.50pm GMT on 23 November