Over 4 million viewers tuned in to last week's new series launch and tonight the show continue with new episode Smile, written by Frank Cottrell Boyce and directed by Lawrence Gough.
The Doctor (Peter Capaldi) will be joined once again by new companion Bill (Pearl Macki), and Nardole (Matt Lucas) with guest appearances tonight from Ralph Little.
In the far future, at the edge of the galaxy, there is a gleaming, perfect city. This brand new human settlement is said to hold the secret of human happiness - but the only smiles the Doctor and Bill can find are on a pile of grinning skulls.
Something is alive in the walls, and the emojibots are watching from the shadows, as the Doctor and Bill trying to unravel a terrifying mystery...
Doctor Who airs tonight at 7:20PM on BBC One.
This year's run is Peter Capaldi's last as the Doctor, previously announcing he would be stepping down after this year's Christmas special.
Capaldi first stepped into the TARDIS in 2013, and will leave the iconic role in the 2017 Christmas special after three incredible series of the BBC's global hit sci-fi drama.
Peter Capaldi said ahead of the current run: "One of the greatest privileges of being Doctor Who is to see the world at its best.
"From our brilliant crew and creative team working for the best broadcaster on the planet, to the viewers and fans whose endless creativity, generosity and inclusiveness points to a brighter future ahead. I can’t thank everyone enough. It’s been cosmic."
Peter Capaldi's final series also marks writer and executive producer Steven Moffat's last.
He said: "Like Peter, I’m facing up to leaving the best job I’ll ever have, but knowing I do so in the company of the best, and kindest and cleverest of men, makes the saddest of endings a little sweeter. But hey, it’s a long way from over.
"Peters’ amazing, fiery, turbulent Doctor is still fighting the good fight, and his greatest adventures are yet to come. Monsters of the universe, be on your guard - Capaldi’s not done with you yet!”