Sharon Horgan and Holly Walsh have revealed how Jennifer Saunders was their "dream casting" in their new prison comedy Dead Boss.

The Absolutely Fabulous star plays over-familiar governor Margaret in the new BBC Three show about a woman called Helen (played by Horgan) wrongly imprisoned for the murder of her boss.

"She was begging to be in it," joked co-writer Holly about Saunders' casting. "She didn't have any work on and things were really downhill for her..."

"No, she was our dream casting. We were begging her," she added, seriously.

They took it as a good sign that, despite being warned that Jennifer took ages to read scripts and respond, she signed up to play Margaret just one day after receiving the script.

"To find out so quickly, we were just made up. And she couldn't have been nicer, and everything she did on screen was so funny. We're all obsessed with her. And we are going to be her friend one day," laughed Sharon.

While Sharon took centre stage in Dead Boss, Holly - who is a panel show regular and former CBBC presenter - preferred to be behind the scenes. Although she does pop up in one scene.

"I do make an appearance. I don't know how long you have to be on camera to win a Bafta but..." she joked.

:: Dead Boss starts on BBC Three on Thursday, June 14.