Movie veteran James Brolin has applauded his actor son Josh's business savvy because playing villain Thanos in the last two Avengers movies has set him up for life.

The Amityville Horror star gave his son some sage advice at the beginning of his acting career, and now it's really paying off.

"I told him one thing a long time ago... I did tell him one great thing: 'Don't be a leading man, ever. Be a character actor and you'll work forever...' so look at him; he takes this movie with Thanos and I go, 'I didn't mean that!'" he said during an appearance on Access Daily. "It's the biggest thing. He doesn't have to work again. He wasn't paid upfront and he took a piece of the back (end profits) ... I'm so proud of him."

And Josh is making the most of his newly-acquired fortune, taking a year off to be a dad.

The actor and his wife Kathryn Boyd welcomed daughter Westlyn in November 2018.

"He's a diaper-ing fool," the 79-year-old joked. "That's what the last year has been, literally. I don't think he's worked much... I just heard that Mel Gibson and he may go to Australia to do a remake of The Wild Bunch."

But while James thinks his son made a clever career move by appearing in the Avengers films, he has no idea what happens in the final movie.

"I didn't understand that movie... I understand the cost and the profit, I don't understand the story," he sighed.