David F. Sandberg was astonished that Dame Helen Mirren and Lucy Liu agreed to star in 'Shazam! Fury of the Gods'.

The 41-year-old director is helming the DC Extended Universe (DCEU) sequel that will feature Helen and Lucy as villains Hespera and Kalypso respectively and the filmmaker said he was beyond his wildest dreams to cast the pair.

Speaking at San Diego Comic-Con, David said: "I mean, it's a dream come true, first of all. I've been watching movies with Lucy and Helen, and now I get to work with them – which is just amazing.

"They're just the best. When we had these parts, we were like, 'Let's try and get the biggest and best actresses we can.' And we were able to, because they said yes. It's amazing."

The upcoming blockbuster is a sequel to the 2019 film 'Shazam!' and sees Zachary Levi return in the title role and Sandberg explained that a follow-up was never in any doubt.

Asked when Warner Bros. contacted about making the flick, David told Collider: "The first movie just came out, and we were already having meetings about what's the sequel going to be and trying to figure that out. Didn't feel like there was ever a point of like, oh, is there going to be a sequel or not?"

David explained how test screenings held for the movie enabled him to improve the final cut.

The 'Lights Out' director said: "It was mostly actually tightening up in some places. There's a lot of stuff going on with monsters and everything. We had some sequences that were really cool that had a lot of monsters, but it didn't really involve the family.

"It felt like, well, you can probably take that out because people want to see more of Shazam and the family, even though the monster's just creating havoc and cities are cool too."