Josephine shared a video of her squirming as she practised holding the crab before filming.
She explained: “Just so you know, I’m terrified of spiders, it’s a real phobia and people who have the same phobia will understand crabs are like huge massive spiders.
“It’s even worse it’s like a nightmare so I did the scene and I was decomposed, gone, dead inside.”
While appearing confident on camera and reassuring her colleague the crabs are fine on-screen, she admitted: “I’m literally crying and terrified.
“But, I did it the first time, I was so proud of myself.”
Death In Paradise continues Thursday at 9pm on BBC One.