10.2 million tuned-in on Christmas Day to get their first glimpse of Capaldi in one of TV's most iconic roles in the festive special "The Time of the Doctor", which saw Matt Smith hang-up his bow tie after 4 years in the role.
Capaldi was revealed as the Doctor in a live BBC One show in August, after months of speculation about the next Doctor's identity.
Arriving on set in Cardiff to begin filming, Peter Capaldi had this to say in a statement.
"New job, first day, slightly nervous. Just like the Doctor, I'm emerging from the TARDIS into a whole other world."
Steven Moffat, Lead Writer and Executive Producer, added the following statement.
"First the eyebrows! Then, at Christmas, the face! Coming soon, the whole Doctor. In the Cardiff studios, the Capaldi era begins."
Accompanying the Doctor on his adventures will be companion Clara Oswald, played by Jenna Coleman.
The first episode of Season 8 has been written by Steven Moffat with the second episode penned by Phil Ford. These are the first episodes that Peter will shoot and are directed by Ben Wheatley.
Ben Stephenson, Controller of Drama Commissioning, had this to say in his statement.
"Excitement and anticipation fills the air as Peter Capaldi's Doctor takes control of the TARDIS for the very first time today. It's going to be one hell of a ride and I can't wait for the journey to start."
Charlotte Moore, Controller BBC One, released her own statement.
"A new year, a new face, a new Doctor! 2014 has arrived and it's Peter Capaldi's time so let the adventures begin!"
Filming is taking place in Cardiff until August 2014. Doctor Who is executive produced by Steven Moffat and Brian Minchin, and produced by Nikki Wilson and Peter Bennett. It is a BBC Cymru Wales production for BBC One.