Justin Timberlake says being a father has "changed everything".

Justin Timberlake

Justin Timberlake

The 'Mirrors' hitmaker - who welcomed Silas Randall into the world 18 months ago with his wife Jessica Biel - has a "new appreciation" for his other half since the arrival of their son.

He said: "It changes everything. You literally wake up and look in the mirror and go, 'I have no idea what I'm doing!'

"It's crazy. This new appreciation for both of them, her and him, it's humiliating and it's humbling at the same time ... You watch her realise she has a gear she [thought she] didn't have and then you go, 'Woah, yeah.'"

And the 35-year-old actor believes he wouldn't have been able to pen his hit track 'Can't Stop the Feeling!' if he didn't become a father.

Speaking on The Today Show, he added: "I would have never written a song like 'Can't Stop the Feeling!' [if I wasn't a father].

"I don't know that it was directly inspired to be something that my son could listen to of mine, because there's a lot of music he can't ... at least not yet ... [but he was an influence]."

Meanwhile, Justin previously revealed he has a different outlook on life since welcoming Silas into the world.

He said: "I'd be leaving out the whole truth if I didn't say having him shaped what the song actually is. [Having a child] gives you a different insight. It's like 'The Matrix,' man. You open a door and there's this whole other world on the other side of it. And you look back through the door at the other world and you're like, 'What was I doing there?'"