In an official interview to promote the hit sequel, the actress credited the music of ABBA with making Here We Go Again so resonate.
The movie has had a strong performance at the box office worldwide, and has also received a far better than expected reception from most critics.
“It’s overwhelming, and it’s unbelievable because we never thought ten years later we’d be back,” Streep said prior to the sequel’s release date.
“And I think the world needs Mamma Mia more than ever.”
On what makes the series – which started with the 2008 original – so successful, she said: “It’s ABBA and it’s the music – there’s something about the music, it’s so enlivening and it’s about summer and falling in love and losing love and never losing love.”
Meryl has three song appearances on the soundtrack, one of which – The Day Before You Came – does not feature in the movie itself.
“[Recording] was fantastic and we did the recording in the same little chapel, a recording studio near Hampstead where we recorded the original.
“We went right back in and did the second version and it felt like a gift.”
Joining Streep in the returning cast are Amanda Seyfried, Christine Baranski, Julie Walters, Pierce Brosnan, Dominic Cooper, Stellan Skarsgard and Colin Firth.
Seyfried plays Streep’s on-screen daughter Sophie, and she said of her performance: “I think Amanda brings something to this particular incarnation of Mamma Mia that’s very special.
“She’s the heartbeat of the film. Her emotion carries the whole story forward and she really moved me.
“I think she’s magic.”
Cher has joined the fun as Donna’s mother Ruby, while Lily James plays the younger Donna.
Mamma Mia: Here We Go Again is out now.