His final series will also end with the departure of writer and executive producer Steven Moffat.
Capaldi told BBC Radio 2: "One of the greatest privileges of being Doctor Who is to see the world at its best.
He had a role in Capaldi’s first Doctor Who series, and would fit the typical nerdy vibe associated with the show Word is that Hayley Atwell, aka the Marvel Cinematic Universe’s Peggy Carter, is keen to play the Doctor – and a big fanbase would be thrilled to see that happen.
She starred in the second series of Broadchurch, so she’s certainly on showrunner Chris Chibnall’s radar If Chibnall continues in the typical Doctor Who mould, Jonathan Bailey is a strong bet.
Billie Piper is set to follow her co-star Christopher Eccleston in quitting Doctor Who, according to reports.
The 22-year-old, who plays the Doctor's assistant Rose Tyler, will return for the new series but it is not confirmed for how many episodes, a BBC spokeswoman said.
"With regard to how many episodes she will be in, we are currently story-lining series two," she said.
Piper is thought to appear in just three episodes of the next series.
A BBC spokeswoman said plans for the second series had not been finalised.