Dax believes his urges may have been the start of an addiction. Picture: Reuters

Dax Shepard thinks he used to have a sex addiction.

The 44-year-old actor - who has been married to Kristen Bell since 2013, with whom he has daughters Lincoln, five, and Delta, four - believes that he once battled an addiction to sex, because he says that following an argument with a former girlfriend, he found himself struck by “horniness”.

Speaking to Dr. Phil McGraw on the Phil in the Blanks podcast, the Parenthood star said: "I'd say I've had what could maybe be called a sex addiction at some point in my life. Not one that I had to seek treatment for, but … Up until then I would just say, 'I've had sex with a lot of people. I like to do it. It's healthy. Who cares? I'm not getting diseases. I'm single. Whatever.’ 

“The moment that I thought ‘Oh this deserves exploration’ is when I had a girlfriend, she was away, we got in a fight over the phone, I hung up the phone, I was driving in the car and I immediately got horny.”

Dax believes his urges may have been the start of an addiction, because he says his brain was “taking care” of him by making him feel aroused so that he didn’t feel the pain of his argument with his girlfriend.

He added: "Now, that is a biochemical feeling; I'm getting a serotonin dump. Whatever I'm getting, that's a physiological thing: horniness. So, I'm just feeling authentically horny. And I think, 'Hmm, I'm going to text this girl I know.' And I text this girl - and there was a delay. And then I just had this moment of clarity. I was like, 'That's suspicious. I just felt disempowered by my girlfriend and immediately I got horny. Could me brain be, like, taking care of me?'"

Dr. Phil even agreed that Dax could be right about his thoughts, as he says his brain “assigned the meaning” to his emotions.

He told the When in Rome actor: "Think about it: For every thought you have, there's a physiological corollary. You assign the meaning to it: This is sexual arousal, this is fear arousal, this is excitement arousal, [so] you just point it in whatever direction your mind wants to take."