Good Morning Britain host Kate Garraway was left both flabbered and ghasted, in that order, on the show today after co-star Ben Shephard made a rather risqué sexual joke at her expense.

The 50-year-old was left with her mouth on the floor, quite literally, after he dropped the oral sex innuendo during the news segment.

He made the crude, but admittedly hilarious, remark after Kate said that a recent study revealed that smiling makes people look older, and that the best way to combat this was by looking surprised.

“A big grin makes us appear three-and-a-half-years older,” she explained to Ben and co-host Susanna Reid.

She continued: “Apparently, if you want to stay younger you have to adopt an expression of surprise and shock because that stretches out the facial lines.”

Ben asked: “How do you do that?” Kate then proceeded to open her mouth as wide as she could in a bid to adopt a shocked expression.

“Yes, I had a girlfriend like that,” Ben quipped in response as he started chuckling playfully.

However Susanna, 42, lifted the tone to more family friendly heights as she assured Kate: “But as we know, you look fabulous at 50.”

“I think it’s a bit of a weird reaction. You look younger but you just look a bit odd,” Kate reflected, adding: “Someone says good morning, how are you, and you do this.”

Kate did the shocked expression again, sending her co-presenters into fits of giggles once more.

See the joke for yourself in the video below