Amanda Seyfried Teases the Possibility of 'Mama Mia 3' (Exclusive)

Amanda Seyfried offered up a few more details regarding last week's mysterious announcement she was working on an unnamed musical.

Here we go again... again? Amanda Seyfried offered a few more details on Sunday regarding last week's mysterious announcement she was working on an unnamed musical following her Golden Globes absence. Fans online hoped she was speaking about a new installment of Mamma Mia

Seyfried missed the Golden Globes ceremony last week -- presenter Mo Brings Plenty explained that she was "deep in the process of creating a new musical" when he announced her win for Best Actress in a Limited Series for her performance in Hulu's The Dropout. 

Seyfried arrived at Sunday's Critic's Choice Awards in-person, and told ET's Denny Directo that while the Golden Globes absence was not related to a potential expansion of the Mamma Mia universe, she is "waiting for the call" to join a third installment. Seyfried played Sophie in the 2008 film and then reprised her role in the 2018 sequel. 

Instead, the cryptic Golden Globes announcement turned out to be news that Seyfried is workshopping a musical about Thelma and Louise with Evan Rachel Wood. 

"The creators are working diligently to bring something beyond comprehension to life onto the stage," she said. 

Seyfried added that she didn't mean to be dramatic with the Golden Globes announcement. "It was just honestly, I just wanted to give a bonafide explanation as to why I missed it," she said. "I didn't want that generic, 'Can't be here tonight.'" 

Seyfried didn't have any details on the project's timeline, but told ET "it's going to be a while." In the meantime, she emphasized how excited she was to see the project come together. "We've got all the right people involved," she said. I'm not scared at all." 

Though the timeline may be long, it appears to be peppered with several potential musical projects along the way. As the Mean Girls Broadway musical makes its way to a movie adaptation, Seyfried added that she would be "very open" to making a cameo in the film. 

"It's evolved so much in a new way over the years," Seyfried said, who starred as Karen Smith in the original 2004 Mean Girls film. "That was my first movie. It's so beloved and I just don't see it ever ending. I hope it never stops evolving. "

Seyfried's next upcoming project listed on her IMDb is The Crowded Room, set to be released in 2023.