'We're not crying, you're crying': Toddler wins hearts with adorable viral 'Dinosaurs in Love' ballad

Her dad had no idea that the three-year-old even cared about dinosaurs.

When London-based musician Tom Rosenthal's youngest daughter Fenn wandered into his recording studio and asked if they could write a song, even the proudest father couldn't have predicted that the adorable resulting ballad would become an instant smash hit on social media.

Rosenthal had no idea that the three-year-old even cared about dinosaurs, until she started singing "Dinosaurs in Love," which takes the listener on a magical minute-long journey inside the mind of a toddler, taking in a prehistoric love affair, cucumber-munching dino parties and the big bang.

The 33-year-old songwriter told ABC News that his daughters Fenn (3) and Bess (6) often wander into his studio to write and sing songs together.

“Fenn has written quite a few songs,” Rosenthal said. “Fenn and Bess make up the words and I’m just kind of helping them construct a song as they go along," he continued. "But, this time, it was just me and the little one."

Rosenthal said Fenn walked in to the studio and asked if if they could do a song, and since his answer is almost always yes, he asked her what it should be about.

“Dinosaurs,” Fenn said, according to her dad.

“She just started singing about Dinosaurs. It comes out in little bits. She’ll take a break and then come back — she just needs a point in the right direction. I’ll ask her, 'what might happen next?' And the words just come straight from her head. I had no idea she knew about dinosaurs, but I know her sister tells her stuff, and she’s a bright little kid.”

The poignant ditty starts off in high spirits, before taking a heartbreaking turn that struck an emotional chord with fans on Twitter, where Tom's tweet had notched up 2.4 million views and over 35,000 retweets at time of writing.

"We're not crying you're crying," London's Natural History Museum tweeted.

Meanwhile, music streaming service Spotify asked if the young musical prodigy had decided on an official release date for the viral sensation.

For fans looking to sing along, the lyrics, straight from the mind of the talented toddler, are: "Dinosaurs eating people. Dinosaurs in love. Dinosaurs having a party, they eat fruit and cucumber. They fell in love. They say 'thank you.' A big bang came and they died. Dinosaurs, dinosaurs fell in love but they didn't say goodbye. But they didn't say goodbye."

"The end hit me like a meteor," one listener commented.

ABC News' Lena Camilletti contributed to this report.