Ahead of tonight's premiere The Bells of St. John, airing March 30th on BBC America, Doctor Who revealed some of the all-star cast that will mark the 50th anniversary. David Tennant and Billie Piper will join current Doctor and companion, Matt Smith and Jenna-Louise Coleman, while John Hurt will also co-star.

Last seen as the Doctor on January 1, 2010, this will be the first time David Tennant has reprised his role as the Tenth Doctor. During his reign as the Time Lord, David Tennant appeared in three series as well as several specials. He was first revealed as the Doctor in the 2005 series finale, The Parting of the Ways.

Meanwhile Billie Piper, who played companion Rose Tyler for two series following the reboot in 2005, will appear in the show for the first time since featuring in David Tennant's last episode, The End of Time in 2010.

Also confirmed to join the cast is John Hurt who will also co-star in the anniversary special that will form part of blockbuster celebrations. Produced by BBC Cymru Wales for BBC One, the 50th anniversary will be written by Steven Moffat and Directed by Nick Hurran.

Filming for the 50th anniversary begins this week in the UK. Meanwhile, Doctor Who returns to BBC America tonight, March 30, 8:00pm ET/PT with eight epic episodes, which officially introduces the Doctor's newest companion, Clara Oswald, played by Jenna-Louise Coleman. Doctor Who will be immediately followed by the world-premiere of new original series Orphan Black at 9:00pm ET/PT and Chris Hardwick's The The Nerdist at 10:00pm ET/PT as part of BBC America's Supernatural Saturday.

All-new special, Doctor Who: The Companions, premieres Sunday, March 31, 7:00pm ET/PT. As the Doctor's newest companion, Clara Oswald, steps into the TARDIS, take a look back at previous companions that have won over the Doctor's heart in Doctor Who: The Companions. Along the way, companions old and new talk about how the show has changed their lives, and how they've never quite managed to leave the TARDIS behind. Matt Smith and David Tennant are joined by fellow contributors including John Barrowman (Captain Jack), Arthur Darvill (Rory) and Noel Clarke (Mickey).