The 35-year-old singer and his wife Jessica Biel welcomed their son Silas Randall into the world 19 months ago, and the 'Rock Your Body' hitmaker is still not over the joys of being a parent.
Speaking to Australian news programme 'Today', which aired on Tuesday morning (15.11.16), the star said of becoming a father: "It's the greatest thing that's ever happened to me.
"It was nice to have the time to just be there and enjoy the first year."
The 'Cry Me a River' singer has previously told fans he's heading back into the studio to create a new album, and joked his motivation came from needing to afford "expensive toddler clothes".
He added on the show: "You've got to pay for those expensive toddler clothes. They cost more than my clothes!"
It wouldn't be the first time Silas has influenced Justin to make music though, as the 'Sexy Back' musician previously claimed the tot had inspired him to write the hit single 'Can't Stop The Feeling'.
He said: "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]."
The star previously revealed becoming a father "changed everything" for him.
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 [Jessica] and him [Silas], 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.'"