Mask slips for oh-so perfect Firths...

THEY seemed to have the perfect luvvie marriage — one that’s lasted 20 years and produced two sons.

He, the righteous Remainer and Oscar-winning actor. She, his Italian wife, a successful film producer, ecowarrior, Oxfam ambassador and member of the #MeToo set.

Which is why Colin Firth’s and Livia Giuggioli’s admission that she had a year-long affair with Italian journalist Marco Brancaccia — a childhood friend she now accuses of stalking her — has shocked us all to the core.

For it explodes the fiction that we have taken for granted about these two champions of sanctimony who have so readily embraced good causes.

Last year, in a huff about Brexit which he described as a ‘disaster of unexpected proportions’, Firth chose to become an Italian.

The actor — described by fellow thespian Rupert Everett as a ‘ghastly, guitar-playing, redbrick socialist’ and a ‘grim Guardian reader in sandals’ — explained it was ‘for family reasons’ and that he wanted the same passport as his wife and children.

Now we learn that a few years ago that same wife had left him and embarked on an affair, although they are now back together.

This week, Livia was in full righton mode, brandishing her moral credentials on International Woman’s Day, tweeting: ‘To all the women out there #sisters #globalfeminists #gamechanger #activecitizens happy.’

The trouble with such smugness, is it sets the couple up for a fall when their apparently perfect life actually turns out to be anything but.

Of course it would be hideous to be stalked. After the man who stalked Newsnight presenter Emily Maitlis for 20 years was jailed, she bravely told how it affected her work, her marriage, her children, decisions about when to leave her house or meet strangers — everything in her life.

If Livia’s claims are true, that her life has been made hell by her spurned lover just because she and her husband chose to live as a family again, Brancaccia should be punished.

But if, as Brancaccia says, her accusations were made simply to cover up the problems in her marriage — that would be a different matter entirely.

One thing is certain: that in this febrile #MeToo world, relations between the sexes are becoming more complicated by the day.