But while it's usually an innuendo that gets the daytime TV pair sniggering, this time viewers weren't actually sure what had got them laughing so hard.
As Holly and Phil tried to present a link after a commercial break, they broke down live on air completely from nowhere.
They then said they were laughing about a text someone on the 'This Morning' crew had once sent to the wrong person, in relation to the phone-in topic on the show, but claimed it was too rude to share the joke.
The twosome still struggled to pull themselves together, with Holly joking that she would have to hand back her Glamour Award for TV Personality, which she had been awarded the night before.
"You have to stop!" Holly told her co-host, as she stepped away from him and sat down.
"You started it!" Phil insisted, as their giggles continued.
"I'm going to cry my eyelashes off," Holly squealed.
Luckily, the pair were able to throw to a VT to give them enough time to calm down.
Watch the infectious moment in the video above.
'This Morning' airs weekdays at 10.30am on ITV.