Will Smith admits his marriage has been "excruciating" at times.
The 47-year-old actor has been married to fellow Hollywood star Jada Pinkett Smith since 1997, and has revealed their relationship has been "grueling".
He shared: "We've been married 20 years and we've been asking ourselves [what's the secret to marriage] and really at the end of the day it's just not quitting.
"You can't expect it to be easy. It's like our marriage was the most difficult, grueling, excruciating thing that we have ever taken on in our lives. And you know we're just not quitters."
Will also revealed what he considers to be the secret to maintaining a good marriage.
The actor - who shares 17-year-old son Jaden and 15-year-old daughter Willow with his wife - told Entertainment Tonight: "I would say is that we never went into working on our relationship.
"We only ever worked on ourselves individually, and then presented ourselves to one another better than we were previously."
The duo have been the subject of numerous divorce rumours in recent months and in August, Will took to Facebook to rubbish the speculation.
He wrote: "So, in the interest of redundant, repetitious, over & over-again-ness... Jada and I are...NOT GETTING A DIVORCE!!!!!!!!!!!!! (sic)"