On the season one finale of Last Tango in Halifax, Celia reacts badly to John’s revelation that Caroline is gay. When she and Alan have dinner with Caroline and Kate, she’s very rude to Kate. Alan feels crushed after this, and tells Gillian that it’s over between him and Celia. Celia duly apologizes to Kate and begs her not to leave Caroline. The next day, Celia learns that Alan has had a heart attack.