Liar is a British thriller television series created by Harry and Jack Williams, and co-produced by ITV and SundanceTV. The series stars Joanne Froggatt and Ioan Gruffudd as two people whose initial attraction leads to far-reaching consequences for them and their friends and families. The series premiered on ITV on 11 September 2017, with the first series concluding on 16 October 2017. Upon its debut, it received positive reviews, with many critics praising the performances of Froggatt and Gruffudd. The programme was renewed for a second and final series, which premiered on 2 March 2020, concluding on 6 April 2020.