Peter Capaldi's first season of Doctor Who is coming to an end, but as the final episode is about to broadcast the actor has appeared as The Doctor in a very special clip indeed.

Video uploader Ross Goodall explains that it is "a lovely message from Peter Capaldi to my 9 year old autistic son. This arrived just before Thomas' nanny's funeral and helped him to deal with his grief in a profound way." 

Check out the clip below, in which The Doctor urges Thomas to "look after yourself, take care and be happy":