Clarke Peters recently appeared in BBC medical drama Holby City
One of the stars of US show The Wire is to play a role in the new Dr Who spin-off animation, Dreamland.
Clarke Peters, who played Lester Freamon in the hit show, will voice a native American called Night Eagle.
The Doctor and Peters' character, who he describes as "an old man but a hell of an archer", are caught up in an alien invasion of Roswell, New Mexico.
Tennant will provide the voice for the Doctor in the six-part series, which is due to be shown later this year.
Peters admits his son has become a big fan of the show and has already got David Tennant's autograph for him.
"Now my son is watching it avidly and he asks me to come and sit down with him just to watch Doctor Who," he said.
The Doctor gets a new assistant called Cassie Rice in Dreamland
The 45 minute animation will be premiered via the BBC Red Button on BBC One and the Doctor Who website.
The date has yet to be announced.
It will also be shown on BBC Two, CBBC and the BBC HD channel this autumn.
The Doctor will get a new assistant in the cartoon. Cassie Rice will be voiced by Georgia Moffett, who previously played the Doctor's daughter in the TV show.