Doctor Who: Matt Smith on the perils of being recognised
The 50th anniversary special of Doctor Who - The Day of the Doctor - is broadcast on BBC One on Saturday.
During its five decades eleven actors have played the role of the Doctor.
Matt Smith told BBC Breakfast about the special anniversary episode and his departure during the Christmas special.
He also explained how once while answering the call of nature, he was spotted by a fan who wanted him to speak to his wife.
The Day of the Doctor is on BBC One at 19:50 on Saturday 23 November.