photo: HBO

One of the biggest movie mysteries of our generation has been solved! Fans of the 2008 Mamma Mia film starring Meryl Streep and Amanda Seyfried have wondered about one huge open-ended part of the film for 11 years. Thanks to a recent episode of Big Little Lies, they think they just might have the answer!

The Mamma Mia film is all about Donna (Streep) accidentally reconnecting with her past lovers to discover who her daughter Sophie's (Seyfried) father truly is. 

Ultimately, their family realizes that it doesn't really matter, and they all accept Sophie as their own regardless of biology. Of course, fans all had their own theories and have stuck by them since 2008. Now Streep's appearance on Big Little Lies has fans thinking they know who Sophie's father is based on her son in the HBO series, Perry (Alexander Skarsgard).

Whew! This gets complicated, but let's break this down.

In Mamma Mia, Meryl Streep is the lovable nomad Donna, who lives in her rundown hotel with her daughter, Sophie (Seyfried).

At the start of Mamma Mia, Sophie is getting married, and all she wants is her father to walk her down the aisle. Unfortunately, she has no idea who he is. The 2018 sequel, Mamma Mia! Here We Go Again, tells Donna's side of the story as a young woman falling for three different men. She ultimately chose an independent path. 

Sophie invites the three potential fathers to her wedding in hopes that when she meets them, she'll just know. 

Sophie meets Sam (Colin Firth), Harry (Pierce Brosnan), and Bill (Stellan Skarsgård) after she invites them to her wedding through a letter in which she posed as Donna. Hilarity and songs ensue as the three men reconnect with their past love and new daughter. In the end, they don't really care who the "real" father is; all of them accept her as their own. 

Fans never got over it so easily. The meaningful message behind the movie is admirable, but fans have been theorizing who Sophie's biological father really is since the 2008 release. When the 2018 Mamma Mia! Here We Go Again sequel dropped, its fans wondered about the mystery all over again. 

Up until recently, Bill (played by Stellan Skarsgård) was just one of the contenders who could possibly be Sophie's dad. 

Bill is the charismatic sailor and adventurer with bright blue eyes and blonde hair (very similar to Sophie's, might I add). In the sequel, he was played by the ever-so-dreamy Josh Dylan, who looked even more like Donna's future daughter. 

The young Donna (Lily James) and Bill have a fling aboard his boat before he leaves to sail around the world, and they don't meet again until that fateful wedding. 

Other than the striking resemblance between Bill and Sophie, fans had no real proof that Bill could be Sophie's biological father until the season two premiere of Big Little Lies. 

This is where it gets a little tricky. Alexander Skarsgård is Stellan's oldest son in real life and he played Perry in Big Little Lies. 

Alexander Skarsgard "Big Little Lies"
photo: HBO

Alexander played Nicole Kidman's abusive husband, Perry, who (SPOILER ALERT) died at the end of Big Little Lies' first season. The first episode of season two addressed the aftermath of his death and how Celeste (Kidman) and her two sons are coping. Perry's mother, Mary Louise, comes to help and grieve with Celeste and the boys. 

Here's where it all ties together: Mary Louise, aka Perry's mother, is played by none other than Meryl Streep, aka Donna. Translation: She's the mom to the IRL son of one of the guys who is her potential baby daddy in Mamma Mia! Are you with me?!

Meryl Streep is a grieving mother in Big Little Lies season two, but the connection between the real-life actors is what gave fans the answers they've been searching for. 

Meryl Streep in "Big Little Lies"
photo: HBO

Streep's performance as Mary Louise in the first episode blew fans of the show completely away. The iconic scream heard around the world trended on Twitter, and Jimmy Fallon talked to Shailene Woodley on his show about how he couldn't get over her facial transformation.

But Mamma Mia Streep fans stopped dead in their tracks and pieced together the Skarsgård-Streep-Seyfried on-screen heritage. 

If Donna, aka Mary Louise (Streep), is Alexander Skarsgård's (albeit, on-screen) mother, and Stellan Skarsgård (aka Bill) is his dad, then that means that Bill is Sophie's (Seyfried) real dad and Perry (Alexander Skarsgård) is her brother. Whew!

One fan put it all together on Twitter. 

"If Meryl Streep’s son is Alexander Skarsgård I believe we finally have the answer to who the real dad is in Mamma Mia," one fan made the realization in a tweet, and had people reeling. 

"Does... does this mean that Amanda Seyfried is Alexander Skarsgård's sister? Is this why they have the same initials?" someone replied. 

One person thought that Alexander could have been cast as Young Bill. "This brings me back to my theory that Alexander Skarsgård wasn’t cast as Young Bill because he’s too good looking and it would’ve been distracting + difficult to root for Sam over him," the fan wrote.

Another Bill-believer tweeted, "As I’ve been saying for YEARS, it's BILL. They even look exactly alike when he’s younger! End of discussion."

Then HBO added to the speculation by replying to the tweets to jokingly *confirm* the news. 

"Watch this space for Mary Louise's rendition of 'The Winner Takes It All,'" the network tweeted in a reply. 

Get it?! "The Winner Takes It All" is a song from the Mamma Mia! film and musical. Obviously, HBO was kidding about the Mary Louise x Donna crossover (even though that would be the crossover event of the century), but it does give Mamma Mia fans further proof that Bill is Sophia's father. 

Case closed. Unless we get a Mamma Mia three, of course.