Former Doctor Who showrunner Steven Moffat revealed that there was a different, more heartbreaking ending planned for River Song and the Twelfth Doctor.

In 2015, Alex Kingston reprised River in the Doctor Who Christmas special “The Husbands of River Song,” which saw her meeting Peter Capaldi’s Twelfth Doctor for the first time. This adventure also ended up being the last time the adventuring Time Lord would see her alive, as River would soon die within her personal timeline. Moffat has now opened up about River and the Twelfth Doctor’s final moments were going to call back to the events of “Silence in the Library” and “Forest of the Dead” from Doctor Who season 4.

While appearing on The Whoniverse Show, Moffat, who wrote the aforementioned two-parter and served as Doctor Who’s showrunner from 2010 to 2017, recalled what he described as a “terrific scene” that had been crafted for the characters, though he stopped short of calling it a full-blown “story.” In his words:

One day when River Song and the Doctor are living their lives on Darillium, the Doctor would realize the message is about to come through for River, and she’d get the message, and they say, ‘Come to the Library.’ And he knows that’s it. That when she leaves, he’ll never see her again. That’s the end of the story for him. But he can’t let her know as she walks out the door that he’s never going to see her again. So that would have been a great scene to do. Just, ‘I’ve got to go to the Library. It’s one of your former selves. I don’t know which one. I’ll just go and see him.’ And he’s going, ‘What is it? Mind me? Oh, it’s some library.’ And he goes, ‘That’s it.’ It ends here, and he can’t show it.

David Tennant’s Tenth Doctor met River for the first time in “Silence in the Library,” whereas, from her perspective, she’d already had many years of adventures with the Time Lord in his various forms. River sacrificed her life in “Forest of the Dead” to save the people stored within the Library’s computer, and before she died, she recalled to the Tenth Doctor about how she’d last seen his future self on a date night at the Singing Towers of Darillium.

This encounter was finally shown in “The Husbands of River Song,” with the Twelfth Doctor taking River to Darillium to spend a night there, which lasts 24 years. Moffat didn’t clarify whether this scene referencing the Library was meant to be included in the 2015 Christmas special, or as a bonus feature on its home release. He also didn’t explain why the scene didn’t make the special’s final cut, but he’s confident that Capaldi would have effectively captured the restrained pain the Doctor felt at that moment.

While “The Husbands of River Song” marked the last time the Doctor saw River, it wasn’t the last time she saw him. Because the Tenth Doctor downloaded her consciousness into the Library’s mainframe, her digital self returned in the 2013 episode “The Name of the Doctor,” where she bid farewell to Matt Smith’s Eleventh Doctor. Kingston has also continued to voice River in Big Finish audio productions set before “The Husbands of River Song.”

The Doctor Who TV show is currently on an indefinite hiatus following the 2026 Christmas special being scrapped, as well as the departure of showrunner Russell T. Davies and production company Bad Wolf. However, Kingson will next be heard as River in the audio series The Death and Life of River Song: River and Rory, which is also bringing back Arthur Darvill as Rory Williams, River’s father.