<P> Lancashire discerned that the series was "very special" within reading two pages of the script . Other factors that persuaded her to commit to the series included the casting of Reid and Jacobi, and the series' juxtaposition of a heart - warming story with elements of humour . In terms of her character, Lancashire identified with Caroline being "a working woman trying to keep everything under control". She stated the series' ensemble cast was "the closest I've come to being in a theatre company on television" due to how well the actors worked together . The cast had all assumed that Last Tango in Halifax would only run for one series . Filming of the second series clashed with filming of the second series of the BBC One period drama The Paradise, which also starred Sarah Lancashire . This necessitated her having to leave her role in The Paradise halfway through the second series in order to reprise her role as Caroline in Last Tango in Halifax . In an interview in 2013 Lancashire stated that the decision to return to Last Tango in Halifax was the easiest she had made in her working life stating "as an actor you can wait an entire career to be involved in a project like this ." The role resulted in her receiving the most fan mail of her career . Lancashire was surprised and humbled by the responses from women stating that Caroline's same sex relationship had personally inspired them . She stated that in her approach to the character she did not focus on Caroline's sexuality, but the "humanity of her". Due to the underrepresentation of gay characters on television, Lancashire felt it particularly important that Caroline's experience would not be portrayed inaccurately . In 2014 Wainwright recalled being "blown away" by Lancashire's performances in the rushes for the series, which partly inspired her to script the series Happy Valley in which Lancashire plays the lead role . </P> <P> Nicola Walker completes the main cast as Gillian . She admired the character's honesty, bravery and lack of self - pity, and identified strongly with her tendency to speak before thinking things through and her deep love for her father . In 2014 The Daily Telegraph described the role as a "game - changer" in the trajectory of Walker's career . Though ultimately successful in winning the role Walker initially believed that she would not get the part due to a lack of confidence in her northern accent, and the presence of northern actresses in the audition . Her approach to the character saw her delve into Gillian's psychology with Walker particularly interested in the contradiction between Gillian's sexual confidence and her use of sex as a form of self - punishment . She felt the series showed a very adult approach to storytelling, stating that she had "never come across a character like Gillian before" and praising the variety of strong female roles . The Independent noted the significance of the series having three female leads over the age of 40, stating that this, alongside Caroline's lesbian storyline and Gillian's attitude towards sex made the series "quietly subversive" when compared against primetime television as a whole . </P> <P> In addition to its main characters, Last Tango in Halifax features a regular supporting cast . Nina Sosanya plays Caroline's romantic partner Kate, who she decides to marry over the course of the series . Gerard Gilbert of The Independent describes the relationship between the couple as "one of the most normalised lesbian relationships ever shown on the small screen ." Nina Sosanya noted that she enjoyed filming with Sarah Lancashire and that the pair would "giggle a lot like completely juvenile idiots" whilst filming their love scenes . Other characters introduced in the first series include Caroline's husband John (Tony Gardner) and his lover Judith (Ronni Ancona), Gillian's brother - in - law, Robbie (Dean Andrews), and Paul (Sacha Dhawan), a youth with whom Gillian has a sexual relationship . Josh Bolt plays Gillian's son Raff, whilst Edward Ashley and Louis Greatorex play Caroline's teenage sons William and Lawrence . The second series expanded the families of Alan and Celia . Timothy West appears as Alan's brother Ted whilst Gemma Jones plays Celia's sister Muriel . The third series later introduces Rupert Graves as Gary, who is revealed to be Alan's illegitimate son, and Michelle Hurst as Kate's mother Ginika . </P> <P> The first series was filmed in Yorkshire and in Altrincham between January and April 2012 . Altrincham was used to represent scenes set in Harrogate, such as those set at Caroline's house . The second series began filming in July 2013 . Filming took place at Holdsworth House in Halifax in August 2013 and also at Hoghton Tower, a fortified manor house in Lancashire, in August 2013 . This resulted in the Tower's being closed to the public between 19 and 28 August . In September the University of York supplied ten students from the Department of Theatre, Film and Television to work as extras on the series . Filming for the third series began in Yorkshire and at Peover Hall, near Knutsford, Cheshire in July 2014 . </P>

Who plays gary in last tango in halifax