The new series of Doctor Who aired on Saturday, and introduced Peter Capaldi's Twelfth Doctor's brand new companion – Bill Pottes. The latest inquisitive and personable companion to discover the TARDIS was meant with widespread praise by fans – but who was your all-time favourite companion, and what are they doing now? Looking at the Doctor's assistants from the show's reboot in 2005, take a look back at the unforgettable stars, and what they have been up to after leaving the show – be it whether they were catapulted back in time, trapped in a parallel universe or just wanted to be the star of their own spin-off!
READ: Kris Marshall as the new Doctor? Fans react as bookies suspend Doctor Who bets
Billie Piper – Rose Tyler
For many Doctor Who fans, the first companion with the reboot – Rose Tyler – will always be one of the best. From a shop assistant to a "defender of the Earth", the heroine definitely changed the most out of anyone by travelling with the Doctor and in many ways, Billie Piper's real-life career was similar to her character as she went from Doctor Who to the critically acclaimed Penny Dreadful to winning an Olivier Award for Best Actress for her performance in Yerma.
John Barrowman - Captain Jack Harkness
Now for a companion who will never really change (until he turns into the Face of Boe of course). Captain Jack was the wise-cracking, flirtatious companion, and John Barrowman continued the character's story in the Doctor Who spinoff Torchwood, which concluded in 2011. Since then, John has found great success appearing as Malcolm Merlyn in Arrow, The Flash and Legends of Tomorrow.
Catherine Tate - Donna Noble
Donna was an hilarious companion to David Tennant's Doctor, but ended up having one of the most tragic send offs after her character was forced to forget everything about her adventures – leading her to revert back to her old self from before she met the Doctor. Since her devastating departure from the show in 2010, Catherine has gone from strength to strength – from reuniting with David for the stage show Much Ado About Nothing to starring in Billionaire Boy.
Freema Agyeman - Martha Jones
Martha Jones was a great assistant, but ended up leaving the Doctor when she developed romantic feelings for him that weren't reciprocated. Since shutting the TARDIS door for good, Freeman has gone on to do a host of TV shows, and landed a role in Sense8 as Nomi's straight talking yet caring girlfriend, Amanita.
Karen Gillan - Amy Pond
Joining the show in 2010, Karen's Amy Pond was a funny and vibrant addition to the show right up until her departure in 2012 thanks to the Weeping Angels. Since leaving the show, Karen has become a film star, appearing in Guardians of the Galaxy and upcoming films The Circle and Jumanji.
Arthur Darvill - Rory Williams
Rory Williams might have died half a dozen times throughout his time as a companion for Matt Smith's Doctor but Arthur made it clear that he wouldn't be returning after he and Amy died midway through season seven of the reboot. Since leaving, Arthur joined Doctor Who alumni John Barrowman on Legends of Tomorrow, and played Rev. Paul Coates in Broadchurch. Addressing his stint on the show, Arthur also performed a hilarious spoof of Let It Go, hinting that he wanted to move on from the sci-fi show.
Alex Kingston – River Song
Although you're never quite sure when the enigmatic River Song might leave Doctor Who, it seemed like Alex Kingston's final, poignant appearance with Peter Capaldi's Doctor marked the end of an era back in 2015. Since then, Alex has been as nonstop as her character, making appearances in Blue Bloods, Happily Ever After and Gilmore Girls: A Year in the Life among others.
READ: Peter Capaldi reveals real reason he quit Doctor Who and hints at replacement
Jenna Coleman – Clara Oswold
Since Jenna's 'the impossible girl' exited the show in 2015 after appearing as the mysterious character Clara (along with her other roles) for the best part of three seasons. After leaving the show, the star landed a huge role in the popular period drama Victoria as a young Queen Victoria, the second series of which will air later this year.
Who is your favourite companion? Comment below!