Downton Abbey's Joanne Froggatt and Mr Fantastic actor Ioan Gruffudd look super-serious (and super-coordinated) in the first-look image for psychological thriller Liar. 

Froggatt became a household name after playing Anna Bates in Downton Abbey, and has since starred as serial killer Mary Ann Cotton in Dark Angel. Now she has been transformed into a school teacher whose life is about to unravel. 

Against a bleak concrete background, she stands alongside co-star Gruffudd, with both characters wearing quilted jackets with the collars turned up. 

Six-part ITV series Liar stars Froggatt as Laura Nielson, a bright and dedicated teacher who is only just adjusting to being single and getting back on the dating scene.

She meets Andrew (Gruffudd), a renowned surgeon whose son is a student at Laura's school. Their initial chemistry leads to a seemingly innocent date.

But the pair each have their lives turned upside down by a series of accusations as that date has far-reaching consequences. Secrets and lies unravel – until the truth reveals itself. 

The six-part series has been created and written by Bafta and Golden Globe-nominated producer/screenwriters Harry and Jack Williams.

Liar is set to air in the autumn.