Dax Shepard had a "deep fear" he wouldn't find love after splitting from Briegh Morrison.

The 50-year-old star was in a relationship with Briegh for nine years, and Dax doubted he'd ever find love again when they broke up.

Speaking on his Mom's Car YouTube series, Dax shared: "The breakup was manageable, but for a while I did think well, I'll never be in love with someone like that again in that way.

"I had a deep fear, like, I don't think I'll ever feel the way I felt about Briegh with anybody. I was quite scared of that."

Dax always remained fond of Briegh, despite their painful break-up. And he was thrilled when she eventually found love with Marvel executive Brad Winderbaum.

He explained to Briegh: "I felt very disoriented for a while. Even though we were in an open relationship, I never felt single. What was hugely important to me from the moment we broke up was, I pray she meets someone she falls in love with.

"I just thought about it a lot. I was so hopeful that you found someone that you loved a lot again. And I just remember being so happy about Brad."

Dax has been married to Hollywood star Kristen Bell since 2013, and he admits that the actress was initially shocked that he remains close to his ex.

Dax said: "She had initially was like, 'This is really wild. I'm not friends with any of my exes. I don't hang out with any'. And I'm like, 'I'm friends with all mine pretty much.'"

Dax also believes that Briegh and Kristen, 45, actually have a lot in common.

He explained: "Something that you guys [both] have that I value so much is I think you two above any other people I've ever met, you have your opinions and your position, but you're really able to listen to another point of view and consider it and integrate it.

"Neither of you guys are, like, stuck. You're very fluid. For me it's an imperative quality.

"I admire both of you so much, and I realise that's a rare thing to get in a partner, and I like you so much. You're just one of the greats of all time. I'm glad our lives worked out so well."