(AGI) Rome, Sept 18 - The BBC's longest-running televisionseries is about to lose one of its most popular performers.Jenna Coleman, who plays Clara Oswald in Doctor Who, will leavethe series soon. First broadcast in 1963, Doctor Who is a BBCscience fiction show whose lead character is a 'Time Lord' - analien time traveller, who calls himself simply "the Doctor". Heexplores the universe in the Tardis, a sentient machine thattravels in space and time through a 'vortex'. Outwardly theTardis looks like an old blue police box, commonly in Britainin the 1960s when the series was first broadcast. The Doctor isalmost always accompanied by a human passenger, with whom hefaces enemies, saves entire civilisations and helps people introuble. Taken off air in 1989, the series was revived in 2005and since then the Doctor's companion has always been a youngwoman. The latest, who starred in the seventh and eighthseries, is Jenna Coleman. The BBC reported that Clara Oswaldwill leave the scene during the ninth series that begins onSaturday. However, it has not been revealed exactly when shewill leave the Doctor. Jenna Coleman debuted in Doctor Who onSept. 1, 2012 as Oswin Oswald in the episode "The asylum of theDaleks". She then returned on Christmas Day of that year,playing Clara and staying with the 11th Doctor (Matt Smith)from the following episode, "The Bells of St. John". Ms Oswaldremained on board the Tardis for all the episodes of the theeighth series with the 12th Doctor, Peter Capaldi. Mr Capaldicommented: "Jenna has been absolutely brilliant. I think she'swonderful in the show, and she's my favourite companion. "The"Impossible Girl" will be in the ninth series, but we don'tknow the number of episodes or how she will take her leave.. .