Mamma Mia 2: Amanda Seyfried admits she thought bosses were 'CRAZY' to make sequel

The new movie comes ten years after the record-breaking original, which starred Seyfried as Sophie and Meryl Streep as her mother Donna.

The new film is a prequel and a sequel, with Lily James playing Donna as a younger woman.

Its reviews have been favourable, with many critics calling it better than its predecessor – but it’s safe to say that many were initially cynical about the decision to green-light a follow-up, including Seyfried herself.

“I had a call a few months before [it was made official] saying, ‘they’re trying to make a Mamma Mia 2’,” Seyfried told Australian TV show Studio 10.

“I was like, ‘they’re crazy!’”

It wasn’t long, however, before her mind was changed – thanks to the Godfather Part II-inspired structure.

“The script was so good, it’s genius,” she beamed. “It’s the only way it could have gone.

“I didn’t know who was going to play young Donna and I found out it was going to be [Lily James] and I was like, ‘oh my God, it’s going to be a good movie!’”

Seyfried isn’t the only one who had her reservations, as Julie Walters – who plays Rosie – has previously spoken about her own concern.

“I couldn’t see how it could work and what they could do with us,” she told Good Housekeeping.

“My first reaction when my agent told me they were making Mamma Mia 2 was, ‘oh God no, it is going to be awful’.