Dwayne Johnson admits Roman Reigns' battle with leukemia was ''very scary''.

The 47-year-old actor recruited his cousin for the action film, 'Hobbs & Shaw', following the WWE superstar's return to wrestling after he announced his cancer was in remission in February and he had overcome the disease for a second time.

And Dwayne - who has Jasmine, three, and Tiana, 15 months with his long-time partner Lauren Hashian - revealed: ''It was a very scary time for him and his family. [For] his wife and his kids and all of us, and for him to come back strong [is great.]''

Reigns added: ''I'm back to 100% in the ring. Life is good. I'm very blessed.''

Dwayne looked to cast a family member in the movie because he wanted the ''opportunity to showcase'' his Samoan culture, but the star insisted Reigns had to go through the rigorous audition process to ''earn his part'' like everybody else.

He told 'Entertainment Tonight': ''When we had the opportunity to showcase my Samoan culture, I thought, 'Well let me go get my real blood'. And, I went out and got Roman Reigns, but he had to earn the part. He sent his audition tape in like everybody else. And once he sent it in, I went, 'Okay good, he doesn't suck! I think he has potential.'''

The 'Skyscraper' star - who plays protagonist Luke Hobbs in the spin-off of the 'Fast & Furious' franchise - explained the much-anticipated film is ''very personal'' to him for ''many reasons'' and has been a ''crazy'' experience.

He continued: ''We cast him and he pops in the movie. It's a very personal movie to me for many, many reasons but the idea that I could bring in my own family and go back to Samoa ... it's crazy.''