Call the Midwife is a period drama broadcast on BBC One.
The cast appeared in a comedy sketch for 2013's Comic Relief which combined elements of the series with that of the Channel 4 documentary series One Born Every Minute. It also featured Matt Smith in a non-canonical appearance as the Eleventh Doctor.
A number of cast members have also appeared in Doctor Who productions individually, most notably Jessica Raine who portrayed Emma Grayling in the Series 7 episode Hide (also directed by Call the Midwife director Jamie Payne). Jenny Agutter and Pam Ferris have also voiced characters for audio dramas.
Similarly there are also a number of other actors who have guest starred in both series, as well as crew members who have worked on both.