Gary Russell previously attempted to have the Twelfth Doctor and River meet in his novelBig Bang Generation, but as Steven Moffat set up The Husbands of River Song to be the Twelfth Doctor’s first, last and only meeting with River, Russell chose to replace River with Bernice Summerfield in the story.
This is the first time in a main story that Alex Kingston’s name has appeared in the opening titles.
River Song previously showed to handle a wiping-memory technology. (The Eternity Clock)
River believes the Eleventh Doctor was the last incarnation of The Doctor because she knew his regeneration cycle was exhausted by then. The Twelfth Doctor briefly mentions how he got past this limit. (The Time of the Doctor)
The Doctor mentions he had a “new haircut”. He is later seen in a suit at Darillium, all in line with what she tells the Tenth Doctor. River would also mention”what a night that was ” when referring back to Darillium, as it turned out to be far longer than she expected. (Forest of the Dead)
The Doctor has avoided Darillium, and is shown to be tearful when he finally makes good on his final date with River.
The Doctor onsce again rewards someone with the means to gain a substantial amount of money. (School Reunion, The End of Time) Interestingly, several people who have encountered The Doctor around Christmastime have now found themselves coming into large sums of money. (Voyage of the Damned, The End of Time)
River pulls a fez out of her bag, an item commonly worn by the The Doctor. (The Big Bang)
The roundels are once again used for storage purposes. In this instance, River has hidden alcohol inside a cupboard behind one of them, to The Doctor’s surprise.
The TARDIS is able to produce a pairof holographic antlers for The Doctor.
River indicates she often steals the TARDIS and returns it before The Doctor notices.
When someone is both inside and outside the TARDIS at the same time, it can’t take off
River states that The Doctor has planned to take her to Darillium numerous times but has always cancelled at the last minute.
River Song owns the bookHistory’s Finest Exploding Restaurants with the tagline”The Best Food for Free, Skip the C offee”. She used it as a source when plotting her escape from the meteor strike that hit the Harmony and Redemption.
River is now 200 years old, revealing she has an augmented lifespan- whether she is referring to the lifespan of a Time Lord or an artificially extended lifespan is unknown.
River has a unique perfume spray that lets her change her clothes as she pleases.
River owns a set of pictures of the first twelveincarnations of the Doctor, which she reveals to clarify that she knows what he looks like. She told The Doctor once that she had pictures of all his faces. (The Time of Angels) This also confirms that River is aware that the War Doctor exists (whom The Doctor once tried to conceal) because she has a picture of him. (The Name of the Doctor)