'Doctor Who' season 9 spoilers: Professor River Song returns for Christmas 2015 special episode

Professor River Song (Alex Kingston) joins the Twelfth Doctor in "Doctor Who" season 9 Christmas special.[Doctor Who | BBC]

Christmas is right around the corner, which means that the Christmas special episode of "Doctor Who" will soon be aired. 

As a treat, BBC America revealed Wednesday that Alex Kingston will reprise her role as Professor River Song in the 2015 Christmas special of "Doctor Who." This will be the first time that the professor will meet the Twelfth Doctor, who is being portrayed by Peter Capaldi. She previously worked with the Tenth Doctor and Eleventh Doctor, played by actors David Tennant and Matt Smith, respectively. 

The synopsis for the 2015 Christmas episode reads: 

It's Christmas Day in the future and the TARDIS is parked on a snowy village street, covered in icicles, awaiting its next adventure. Time traveler River Song meets her husband's new incarnation, in the form of Peter Capaldi, for the first time this Christmas."

Kingston admitted to BBC that she honestly had no idea if her "Doctor Who" character would still return to the show, but series creator Steven Moffat called her to join the Christmas special. She also shared how her first meeting with the new Time Lord went.

"I met Peter for the first time at Monday's read through, we had a laugh, and I am now excited and ready to start filming with him and the 'Doctor Who' team. Christmas in September? Why not!" the actress said. 

But before the Christmas special, "Doctor Who" season 9 will first air this month. The upcoming season will feature "Game of Thrones" star Maisie Williams in an important guest role. According to reports, the 18-year-old actress will appear in episodes 5 and 6 titled "The Girl Who Died" and "The Woman Who Lived." 

Moffat earlier said that William's still undisclosed character will be facing some vicious enemies, including several Vikings and robots. Other reports claim that the character will have a very significant relationship with the Time Lord. 

"Doctor Who" season 9 begins on Saturday, Sept. 19, on BBC America.