Dax Shepard admits his marriage takes a "tremendous amount" of work and therapy

He told Us Weekly magazine: "We don't believe in The One. We don't believe in the fairytale. We don't believe that you can meet someone and you have a perfectly matching personalities.

"We are opposites and it has taken a tremendous amount of work and therapy for us to co-exist.

"My only fear is that people see us and think, 'Oh, I just need to find my Kristen Bell.' That's not true. You'll find your Kristen Bell but guess what, now the work starts.

"[Relationships] are labour intensive. If you want them to last they are labour intensive."

The 'Parenthood' actor - who has Delta, two, and Lincoln, four, with Kristen - recently admitted he likes to do romantic things for his wife.

Asked about the most romantic thing he has done for Kristen, he said: "We got into this really crazy one-upmanship of - so she was doing a movie in Alaska and I was shooting 'Parenthood' and I couldn't go and she was going away for a long time. But then my schedule changed and I didn't tell her, so I got the seat next to her on the airplane and then I sweet-talked the gate representative to let me on the plane early.

"So when she went to sit down, I was in her seat reading a newspaper and she kept going, 'Excuse me, sir. Excuse me, sir. I think you're in my seat.' And then she noticed those hands look familiar and then she started bawling when she saw that I was on the flight. And then so she did it to me on the way back."