Sydney Sweeney is "obsessed" with Amanda Seyfried

During an appearance on The Tonight Show Starring Jimmy Fallon, Sydney shared: "Did I know Amanda before this? I'm obsessed with her. She knows how much I am with her. I am like the biggest Mamma Mia! fan."

The Hollywood duo previously sang along to ABBA's Angeleyes for a TikTok video, and Sydney loves that her co-star agreed to perform with her.

She said: "All my dreams came true! It was amazing."

Sydney revealed that she built a strong off-screen relationship with her co-star, and she described Amanda as an "icon".

The movie star said: "I'll play Mamma Mia! ... My girlfriends and I were on a trip, and we were in Africa, and I was playing the song, we were dancing on the beach, and I sent a video to Amanda, and I was like, 'You are forever my icon.' Like, I love her."

Amanda previously lavished praised on Sydney, describing her co-star as "beautiful and fun".

The actress admitted that she loved working with the blonde beauty - who has enjoyed a meteoric rise in recent years - on the new psychological thriller film.

Speaking to People, Amanda explained: "I think she's beautiful and fun. And we definitely love what we do, and we love the project so much, so it's infectious. We saw the movie and we both loved it."

Amanda has also been busily promoting The Testament of Ann Lee, her new historical drama musical film, in recent times, while Sydney plays the lead in Christy, the new sports drama movie.

Amanda shared: "We were just together last week because we're doing a lot of promotion for The Housemaid movie. It's really crazy timing.

"Our independent movies are premiering the same day, within hours of each other."