John Travolta believes the key to his happy marriage to Kelly Preston is being able to laugh at one another.

The 'People V. O.J. Simpson: American Crime Story' actor admits he and his spouse - who he wed in 1991 - experience their fair share of ''stress'', but are able to overcome their problems with humour.

He said: ''We just have a great sense of humour about each other. You know we have the stress that everyone else has, but also there's the moment... I don't know why I'm laughing, but we have that ability to have good fun at each other, you know.''

And the 62-year-old star loves spending time with his ''exceptional'' children, Ella, 16, and Benjamin, six.

He told 'Extra': ''They're exceptional. That sounds like bragging... they are are exceptional children. I really like them as people as much as I love them as a father.''

Kelly recently revealed she makes John dress up as his characters when they are home alone.

Asked if she first saw John's portrayal of lawyer Robert Shapiro in 'The People v. O.J. Simpson: American Crime Story' on TV, she said: ''No I saw it at home. I would make him do it.''

And when 'Extra' presenter Mario Lopez quipped they were doing ''a little role-playing'', she said: ''All the time. I make him play all the characters. You kidding me?''

And John previously revealed the birth of Benjamin a year after he and Kelly tragically lost their oldest son Jett, who suffered a seizure and died at the age of 16, had helped ''rebond'' their family back together.

He said: ''We certainly have bonded together.

''Certainly having little Ben has been a beautiful kind of glue for us to rebond after a tremendous loss.''