1st trailer for 'Mamma Mia!: Here We Go Again' released

— -- Mamma Mia, they are back!

The first trailer for "Mamma Mia! Here We Go Again," the sequel to the hit 2008 musical film "Mamma Mia!, was released today, and the film's original cast is back.

Meryl Streep, Julie Walters and Christine Baranski reprise their roles as best friends Donna, Rosie and Tanya. Amanda Seyfried and Dominic Cooper return as Donna's daughter Sophie and her beau Sky. And Pierce Brosnan, Stellan Skarsgard and Colin Firth are back to play Sophie’s three possible dads: Sam, Bill and Harry.

This time they are joined by "Cinderella" and "Baby Driver" actress Lily James.

Early in the trailer, Sophie confides to Rosie and Tanya, "I'm pregnant but I don’t know how to do this myself."

The two friends then share with Sophie how her mother raised her on her own. James plays the young Donna, whose story is told in flashbacks.

Filling the roles of young Rosie and young Tanya are Alexa Davies ("A Brilliant Young Mind") and Jessica Keenan Wynn (Broadway’s "Beautiful"). Young Sam is played by Jeremy Irvine ("War Horse"), and young Bill is Josh Dylan ("Allied") and young Harry is Hugh Skinner ("Kill Your Friends").

Streep does not appear in the trailer, except for in flashbacks from the first film, leaving it open to speculation as to what happened to her character.

But the trailer ends with a special cameo from Donna's mother and Sophie's grandmother, played by none other than Cher. "Grandma, you weren’t invited," Sophie tells her when she shows up unexpectedly. Lowering her glasses, Cher's character responds, "That’s the best kind of party, little girl."

"Mamma Mia! Here We Go Again" debuts in theaters on July 20.