Downton Abbey actress Joanne Froggatt is to star in a new ITV drama exploring the devastating cost of deceit.

The six-part thriller, called Liar, will also feature Fantastic Four star Ioan Gruffudd and will be produced with SundanceTV in the US.

Joanne will play dedicated teacher Laura, who is recovering from a recent break-up – whilst Ioan will appear as Andrew, a renowned surgeon whose son attends Laura’s school.

Joanne will play a dedicated school teacher in the ITV series (Richard Shotwell/AP)

The drama, created by Bafta and Golden Globe nominated screenwriters Jack and Harry Williams, reveals the consequences of one night that changes Laura and Andrew’s lives.

ITV’s new head of drama Polly Hill said: “I am so delighted to have arrived at ITV and to be working with Jack and Harry Williams on Liar”

“They are brilliant storytellers, who have written a gripping thriller that doesn’t shy away from exploring a powerful subject. I’m thrilled we’ve commissioned Liar for ITV and secured such a terrific cast.”

Andrew, a renowned surgeon, will be played by Ioan Gruffudd (Carlo Allegri/AP)

The Williams brothers said: “This story deals with highly emotional and important subject matter, exploring modern issues of gender politics through the lens of a character-driven emotional thriller.

“We couldn’t be happier with the calibre of the team we have working on this.”

The series will start filming in November this year.