Flemming is a supporting antagonist in the Doctor Who Season 9 Christmas special The Husbands of River Song.
He was portrayed by Rowan Polonski.
Flemming was the maitre d' aboard the Harmony and Redemption, a space cruise ship that catered entirely to mass murderers. Due to the staff being required to have a history of indiscriminate killing, it is assumed that he committed some horrific crime before the events of the episode.
He was an old friend of River Song, wife of the time traveller known as The Doctor. When the two of them arrived aboard the Harmony and Redemption, carrying the Halassi Androvar diamond to sell to a mystery buyer, they requested Flemming to deadlock seal the luggage hold containing the Tardis and, unknown to Flemming, the robotic body of King Hydroflax, whose head the diamond was contained in. Unfortunately, Hydroflax tricked Flemming into opening the door and forced him to take him to the Doctor and River Song by threatening to take his head. Having betrayed River, Flemming led Hydroflax's body to her and stole her diary hoping to use it to his advantage, even reading out portions of it in a taunting manner.
However, what nobody except the Doctor and River knew, due to them being time travellers, was that the Harmony and Redemption was destined to be destroyed by a meteor shower. With this knowledge, the two of them manoeuvred themselves into a position where the damaged floor would collapse, allowing them to escape. Flemming and everyone else on board were not so lucky and died in the collision.