Matthew McConaughey believes a successful marriage requires "maintenance".

The 56-year-old actor has been married to Camila Alves since 2012, but Matthew admits that marriage always requires hard work.

During an appearance on the On Purpose podcast, Matthew said: "The honeymoon is all on hope. Honeymoon's only in the perfection stage. It's only in the up in the air."

Matthew acknowledges that the so-called honeymoon period doesn't last forever.

He said: "This is not a popular statement with my wife, but - maybe I'm too practical about love, maybe I'm not romantic enough about it - I don't see how the honeymoon period lasts forever."

Matthew thinks a marriage should be like a "30-watt bulb".

The Oscar-winning star - who has Levi, 17, Vida, 15, and Livingston, 12, with Camila - explained: "Not as bright, but it'll last longer and it's more realistic for you and her. It's more human and it's still lovely."

Despite this, Matthew believes that any successful marriage requires hard work.

He said: "You vow to love each other in say, a marriage for instance - and it's through sickness and health until death. My love's not in question, that doesn't mean it doesn't take maintenance."

Meanwhile, Matthew previously confessed that his career in Hollywood has been "awesome".

The film star was initially reluctant to allow his children to follow in his footsteps, but he ultimately changed his mind after reflecting on his own experiences in the movie business.

Matthew told People: "The first 15 years in Hollywood I was like, 'I'd never want my kid to grow up in the business.' And when I hit about 40, right about the time we had Levi, I looked around at how many special people I've met in my life, how much travel and what an awesome, healthy, cool experience that's been for me in my life. I was like, 'Where are you coming up with this idea you don't want any of your kids to do it?' It'd be a privilege if they would be able to."