Jacobs and Walkinshaw were recently cast as newlyweds Sian and Jez Diamond, who take up respective positions in the science and PE departments in the latest run of episodes.
"We giggle constantly - and far too much on set," Jacobs told TV Times of her working relationship with Walkinshaw. "It's weird for me playing a wife because I've never been a wife in real life.
"But Alex is great and says, 'Come on, don't be shy. It's all going to be fine!'"
Jacobs added that she prefers Sian's wardrobe to the scrubs she had to wear for her previous role as Holby City's Donna Jackson.
She said: "[The clothes are] certainly a step up from Holby. I like Sian's wardrobe. But I'm not used to wearing dresses. Also, I have to wear heels all day. I used to get to 3pm and my feet would be killing me, but now I can wear them all day."
Waterloo Road returns on Wednesday at 7.30pm on BBC One.
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