Secondarily, a continuity announcement can also be a voiceover, usually written and read by talent at the network or channel, rather than a production company, which establishes the narrative continuity of the programme about to be viewed. This usage is uncommon in the 21st century. However, the American experience of the Tom Baker era of Doctor Who — as well as the BBCA premieres of the David Tennant and Matt Smith eras have used narrative continuity announcements in various ways.