"Doctor Who" fans can rejoice, because the time-travelling doctor is returning to BBC with season 9 premiere episode "The Magician's Apprentice" on Saturday, 19 September. However, this season is going to be bittersweet because this will be the last time we will be seeing a beloved actor among the main cast.

BBC has confirmed that Jenna Coleman, who plays the Doctor's (Peter Capaldi) assistant, Clara Oswald, has left the show in order to play young Queen Victoria in the upcoming ITV drama "Victoria". It is not known which Coleman's last episode will be, but her departure will happen within season 9.

Read More: 'Doctor Who' to Visit India in May; David Tennant Takes Peter Capaldi on Coffee Date

"Victoria" will recreate the British monarch Victoria's early years, which includes her courtship and marriage to Prince Albert. "She is a vivid, strong, inspirational and an utterly fascinating woman in British history," Coleman described the queen, before adding she cannot wait to tell her story.

Coleman has been a part of "Doctor Who" series since September 2012, first as Oswin Oswald and then as Clara, and has been by Capaldi's side at the Tardis for all the episodes that he has been in. Her departure has caused many fans to ask if they will bring back Rose Tyler (Billie Piper), the travelling companion of the doctor (Christopher Eccleston) in series 1 and 2. 

Many requests went along the lines of, "Now that Jenna is leaving, how about bringing back Rose Tyler. That would be fantastic - as the doctor's companion". But will the show runners heed to these requests, is something we will have to wait and watch.

Read More: 'Doctor Who'/'Sherlock' Crossover for Christmas Special?

The premiere episode of series 9, which will be aired on BBC One on Saturday, is the first half of a two parter, second of which is titled "The Witch's Familiar". The episode written by Steven Moffat will see Clara and Missy (Michelle Gomez) looking for the doctor before the Daleks do. Meanwhile, the doctor is at a magical place, where a scary-looking creature is looking for him.

Watch out for series 9 premiere of "Doctor Who" on Saturday, 19 September on BBC One. You can also live stream "The Magician's Apprentice" via BBC iPlayer.