Alonso (Nacho Fresneda) and Irene (Cayetana Guillén Cuervo) both believe that the actor from the TV show Curro Jiménez (1976) looks like their former teammate Julián. Julián was played by Rodolfo Sancho, son of Sancho Gracia who played Jiménez in the mentioned serial.
When Sub-secretary Martí hears that Lucía suffers from ALS, he explains his familiarity with the illness - he explains that a previous Time Department sub-secretary died of it, while contemplating a picture of that person on his wall. The picture really depicts this show's co-creator Pablo Olivares, who died of ELA in 2014 just before the show's premiere.