5. Born Again (Children In Need, 2005)
Back in June 2005 and after just one series, the Ninth Doctor parted ways in an adventure appropriately titled 'The Parting of the Ways'. We see what they did there! Its momentous cliffhanger left Doctor Who's legion of fans to face an agonising wait until Christmas Day to see David Tennant's first official outing in the titular role. Or so they thought at the time, anyway... Fast forward to 18th November 2005 when Pudsey the Bear, and an audience of 10.7 million viewers, were taken back to the TARDIS to witness the fall out of the Doctor's latest regeneration. In an exclusive adventure penned exclusively by showrunner Russell T Davies for Children in Need, the Doctor had just changed before Rose's very eyes, but would she still be able to trust the man she'd loved with a new face? It was a short two-hander which prematurely introduced fans to the sizzling chemistry between David Tennant and Billie Piper, but it would also prove to be largely influential to Doctor Who's future charitable contributions. Did someone say two Doctors?