David Suchet was delighted to be reunited with former Poirot co-star Peter Capaldi on Doctor Who
The pair have met on screen twice already y'know...

He's just joined Doctor Who in a guest star role as "The Landlord" but did you know David Suchet has met many incarnations of Peter Capaldi on TV throughout the years?
The veteran star of Agatha Christie's Poirot shared his absolute delight at having the opportunity to star in Doctor Who and reunite with Capaldi on Twitter.
https://twitter.com/David_Suchet/status/765664951621062657
https://twitter.com/David_Suchet/status/765665666192080896
He also reflected fondly on their previous starring turns on TV together, including this episode of Poirot in 1991.
https://www.youtube.com/watch?v=KvyOJPqz9Ho
https://twitter.com/David_Suchet/status/765670920996421632
And they also faced off in the BBC's 1992 adaptation of The Secret Agent, which was of course recently remade with Toby Jones and Vicky McClure among the cast.
https://www.youtube.com/watch?v=-wvyLomxspg
Bonus points for spotting the other Doctor Who alum in the 92 adaptation of The Secret Agent.