Justin Timberlake's holding on to his youth.
On Tuesday, Timberlake appeared on the Ellen DeGeneres Show for his 24th time and the pop star revealed his reasoning for never growing out of his "childish" ways.
During the Burning Questions segment, DeGeneres, 64, proposed the question, "What did you think you would've grown out of by now but you still haven't?"
Michael Rozman/Warner Bros. Justin Timberlake
To that, Timberlake, 41, said "the Ellen underwear you gave me," referencing a pair of boxer-briefs the talk show host gifted him during her second episode ever in 2003.
After laughing it off, he gave his real answer, "Being childish, clearly." DeGenerous then responded by saying, "Same with me" and "it's a good thing to stay young."
"Having kids, you get to see the world again through their eyes," the "SexyBack" singer said.
He then shared a piece of "really good advice" he received from someone recently on parenting his two sons Phineas, 21 months, and Silas, 7, with wife Jessica Biel.
"Keep your kids as young as they can be for as long as possible," he said, adding that that is the secret to keeping himself young. "Don't let them grow up too fast."
For the rest of the segment, Timberlake suggested they flip roles and he ask the burning questions — considering it would be his last time on the show as the final episode will air at the end of the month.
Michael Rozman/Warner Bros. Justin Timberlake and Ellen DeGeneres
And while Timberlake doesn't often open up about his children, Biel did reveal in September that after having a second baby, she experienced a "relearning process."
"I remember going, 'When does he eat real food? What kind of cream? What bathtub?' I felt like I forgot — it was amnesia," Biel, 40, said on Today with Hoda and Jenna. "I started from scratch all over again, and I didn't expect that. I just sort of thought, 'Well, I'm an expert now. You know, I've done this before, and I can do it again.' No, I needed a full education all over again."
She also detailed the relationship between her two sons, adding that Silas thinks his little brother Phineas is "hilarious."
"He finds him really funny, and the baby thinks that Silas has hung the moon. So, that's really cute," she added. "He, of course, wants to do everything that his older brother's doing and follows him around everywhere. But Silas is the best big brother. He's so sweet, and he's just a lovely guy. We're pretty lucky. They're sweet boys."