Amanda Seyfried felt "so liberated" while making The Housemaid.

The 40-year-old actress starred alongside Sydney Sweeney in the hit mystery-thriller film, and Amanda admits that she relished the experience of playing an unhinged housewife in the movie.

The blonde beauty told W Magazine: "I star opposite Sydney Sweeney, and we have the same shoe size, are the same height, and we giggle the same way.

"It was so crazy--in some ways, that film is like Black Swan or Single White Female, but funny. I got to play so hard.

"The director, Paul Feig, would give me the strangest directions. He'd say, 'Okay, make [Sydney] think you're going to kiss her!' I felt so liberated."

Amanda previously heaped praised on Sydney, describing her co-star as a "sweetheart".

She told Vanity Fair: "I don't envy anything she's going through.

"I've spent a lot of time with her; we just hit it off immediately. She's a sweetheart. She's a very generous, kind person at her core. I have to be honest: I did not have a moment like she's having ever.

"[My Mean Girls costar] Lindsay Lohan, we're buddies, and it's really, really, really harmful to people to have that kind of overnight spotlight. Because any press, good or bad, is still a blinding spotlight, and you have to maneuver and negotiate your way around it and outside of it. It's acrobatics that I don't think most people are capable of figuring it out at that age."

Amanda observed that a sudden rise to stardom can be "dangerous". However, the actress praised Sydney for how she's coped with the extra attention.

Amanda said: "It's just dangerous, because when you have people s******* on you--or idolising you and following you around--it can't be good for your psyche. It can't make you feel safe in the world.

"But I actually admire the way Syd shows up for work. She always has a smile on her face, even if she's miserable. I hope it doesn't change. I hope she doesn't harden. I just want to keep watching her work."