Brendan Fraser kept forgetting his lines on 'The Whale' because he was so in awe of Sadie Sink's performance.

The 53-year-old actor portrays a reclusive man trying to repair his relationship with his estranged teenage daughter in director Darren Aronofsky's drama and he has heaped praise on his 20-year-old co-star, who plays his distant offspring.

He told GQ in a video looking back on his career: "The fluidity that Sadie plays, this beautiful, controlled rage, was breathtaking to me.

"I was constantly going up on my lines. And that's just because I have cobwebs upstairs and I was wearing a lot of gear, but also because I was just slack-jawed. I'm not joking.

"Watching her work — she won the game ball every day we worked, I'm telling you."

And Brendan also praised castmate Hong Chau's "authenticity", crediting her for elevating the production.

He gushed: "She makes everyone better around her. She elevates the material for how personal that she makes it. There's some sort of alchemy going on in her process that makes you believe everything she does or says. ... It's astonishing."

The 'Mummy' actor is generous in his praise of co-stars as he recently applauded Leslie Grace's work as the titular heroine in the now-shelved DC movie 'Batgirl'.

Brendan - who was set to play villain Firefly - said of the 'In the Heights' actress: "Leslie Grace is her namesake. She’s dynamic.

"She gave a great performance. She’s a stone-cold professional. You’re going to see more from her. And I’m looking forward to it."

The studio made the decision to axe the movie following a "strategic shift" in leadership at Warner Bros.

A Warner Bros. spokesperson said in a statement: "The decision to not release 'Batgirl' reflects our leadership’s strategic shift as it relates to the DC universe and HBO Max. Leslie Grace is an incredibly talented actor and this decision is not a reflection of her performance."

'Batgirl' was directed by Adil El Arbi and Bilall Fallah.