The 51-year-old actor stopped by The Tonight Show Starring Jimmy Fallonon Wednesday and expressed disbelief when the host brought up the internet's frequent comparisons between himself and the young heartthrob.
"He might be able to play my dad one day," Ruffalo quipped.
Fallon went on to show a video of Centineo discussing the likeness between him and Ruffalo, something that seemed to shock the older actor.
"Wow. That's amazing. He's way better looking than I was... Are you kidding me?" he questioned when Fallon held up a teen photo of Ruffalo alongside a current one of Centineo. "I wish I looked like that, I swear to God."
When ET Live's Danny Directo and Cassie DiLaura caught up with Centineo in November, he gushed about his celebrity doppleganger.
"I would be so happy to be Young Hulk. I cannot even explain to you," he said of possibly playing a younger version of one of Ruffalo's most well known characters. "That would be so dope. He was my favorite Marvel hero, and the fact that Mark Ruffalo plays him is sick."
"Since I was 15 years old and acting I've been compared to him. A lot of people say we have the same mannerisms and little quirks," he said. "I just look up to him so much. I love his films and I love his work. He has such range."
The interviews came after the internet couldn't get enough of the Centenio and Ruffalo comparisons following Centineo's quick rise to fame when To All the Boys I've Loved Before premiered last August on Netflix.
"I AM DEFINITELY HERE FOR IT," one fan exclaimed of the lookalike actors.
Others pitched a father-son film starring the duo.