Dwayne Johnson, a cast member in the upcoming film "Baywatch," addresses the audience during the Paramount Pictures presentation at CinemaCon 2017 in Las Vegas. Picture: AP

Dwayne Johnson says he is on "high alert" as his partner Lauren Hashian is due to give birth to the couple's second child in less than two weeks.

The 'Fast and Furious' star has to travel to Shanghai to promote his new movie 'Rampage' but admitted that he is on "code red" at the moment as his partner Lauren Hashian is due to give birth to the couple's second child, and Dwayne's third, in less than two weeks.

READ: Dwayne Johnson urges people to open up about mental health

He said: "We're expecting probably within the next two weeks so I'm on Code Red, high alert ... This Friday I've got to go to Shanghai.

"I have got to go, but we have an understanding. As of now, the plan is, because as of now the doctor said we should be ok. The baby should be born when it's due, which is April 25. So we'll see. We're taking a chance here. We're taking a shot. I have to go to Shanghai, then I have to go to London for 'Rampage.'"

And Dwayne - who has Jasmine, two, with Lauren and Simone, 16, from a previous relationship - was the subject of an April Fool's joke from his partner Lauren - but he later revealed he was actually playing a joke on the show's audience.

Speaking on Jimmy Kimmel Live!, he said: "It came early, actually, this past Sunday. [Lauren] wakes me up and was like, 'Hey, you've gotta get up, I'm having the baby!' And it was like a full-on, full-tilt boogie, going 100 mph ... We get in the car and as soon as I'm backing up, she's like, 'April Fools!' ... It's so insane, literally, that story I just told you is complete bulls**t. April Fools!"