Dax Shepard has agreed to take a drugs test whenever Kristen Bell wants him to.

Dax Shepard and Kristen Bell

Dax Shepard and Kristen Bell

The 'C.H.I.P.S.' actor recently revealed he had relapsed after 16 years of sobriety, so since then, he's ordered a number of tests to keep in their home in case his wife feels "nervous" so they can be upfront with one another.

Kristen told Self magazine: “[He said,] ‘You can drug-test me whenever you want. I’m going to buy some tests. I’m going to have them in the house. If you ever feel nervous, I want you to have access to this and I’ll do it, no questions asked.' "

So far, the 40-year-old star hasn't asked her spouse to take a test and is content with the fact he just doing his best to stay sober once again.

She added: “He’s just good at trying, and that’s all you can ask of anyone. No one’s perfect. He’s proven to me that he is committed to evolving and he loves personal growth.”

Dax - who explained earlier this year that he relapsed into taking Vicodin again following a motorcycle accident after several years sober - recently spoke about discussing his struggles with daughters Lincoln, eight, and six-year-old Delta.

He said: "They knew when I relapsed. We explained, 'Well, daddy was on these pills for his surgery and then daddy was a bad boy and he started getting his own pills.'

"Yeah, we tell them the whole thing... They know that dad goes to an AA meeting every Tuesday and Thursday."

And the 'Armchair Expert' star noted his children have already been very supportive of his struggle.

He added: "One of the cuter moments was — I wanna say my oldest daughter was three — back when my daughters wanted to be with me 24 hours a day.

"She said, 'Where are you going?' I said, 'I'm going to AA.' She said, 'Why do you have to go?'

"I said, 'Because I'm an alcoholic and if I don't go there, then I'll drink and then I'll be a terrible dad.' And she said, 'Can I go?'

"I said, 'Well, no, you got to be an alcoholic.' And she goes, 'I'm gonna be an alcoholic'. I said, 'You might become one. The odds are not in your favour, but you're not there yet.' "