Kristen Bell is ''extraordinarily happy'' that her husband Dax Shepard has continued to stay sober.

The 'CHiPs' star has been sober for a whopping 14 years, and his wife Kristen always makes sure to mark his ''sober birthday'' by ''spoiling the hell'' out of her spouse, because she's so proud of him for staying on the right track.

Dax, 44, said: ''[Kristen] spoils the hell out of me. The nicest presents she's gotten me are always on my sober birthday. In fact, my real birthday ... still haven't gotten a present!''

To which 38-year-old Kristen - who has daughters Lincoln, five, and Delta, four, with Dax - added: ''I'm very happy he was born so I celebrate his birthday, but I'm extraordinarily [happy] that he has stayed sober because that's what allows me to have him in my life as a husband and as a father.''

The 'Frozen' actress says she understands ''how much effort'' Dax puts in to his sobriety, so doesn't take it for granted and appreciates every day that the actor stays committed.

She said: ''I know how much effort has to be put into staying sober. I don't mean that to be like, I come home and see him shaking and looking at a whiskey ad or something, [but] there are different elements you have to deal with when you're staying sober. It's a ton of mental control and evolution. It's just impressive for someone to have been that mindful about something.''

Although, Dax has joked he's tired of his wife ''stealing his thunder'' when it comes to his sober milestones, as she always makes headlines for the adorable letters she writes him when the day rolls around.

Speaking in a joint interview with People magazine, he quipped: ''I scrape together 14 years of sobriety, and she writes a little flowery thank you. Now there's headlines all over the country about Kristen's accomplishment of writing this letter. I'm like, 'Just like you to steal my thunder!' I'm the one that went to 10,000 AA meetings. At no point was the message of any of the stories like, 'Good job, Dax.' It was like, 'Can you imagine being loved by a woman like Kristen Bell?'''