Alison King and Rupert Grint became "quite delirious" while working together on 'Sick Note'.
The 'Coronation Street' actress - who plays Carla Connor in the ITV soap - is to appear in the Sky One comedy alongside the 'Harry Potter' star, and she admitted the pair often couldn't help but fall about laughing when they were supposed to be shooting scenes.
She said: "He's an absolute treasure. He's quiet, beautiful, funny and really down-to-earth.
"We got the giggles a lot. He'd just manage to get his face straight and then we'd go off again.
"We filmed last summer and it was so hot. I think we became quite delirious."
Alison is a big fan of the 'Harry Potter' films - in which Rupert shot to fame as Ron Weasley - and once came close to telling a group of Potter superfans that she had been working with one of the main characters from the book series.
She said: "There was one night when I'd gone out of a drink after work and sitting near us were the biggest 'Harry Potter' fans ever.
"I could hear them talking about the films. I wanted to say, 'You'll never guess who we've been working with today?' "
As well as getting along with Rupert, the 45-year-old star also had a "really nice time" with Lindsay Lohan on the set of 'Sick Note'.
She added to TV Times magazine: "I didn't have any preconceptions about her but she was wicked from start to finish. What a babe.
"She's got this silky voice and is gorgeous.
"We had a really nice time together. She seemed like a sweetheart to me."
Tagged in Alison King Lindsay Lohan Rupert Grint