Tommy Little introduced his followers to his 'biological son'. Most of them missed the joke.

On Sunday, Tommy Little did something no one was expecting. He debuted his 'biological son'.

Following his stand-up comedy show, the radio star shared a photo of himself holding a little boy's hand, while a woman held the other. In the caption, he wrote: "Nice to finally meet my biological son last night."

The post received mixed reactions from fans who seemed to have... NO clue what was going on.

"You didn't know you had a son until now?? So many questions...." one comment read. 

Another said, "WTF. Is this real?!" 

A third person wrote, "Welcome to the greatest love affair of your entire life."

What these three commenters all have in common — along with a few thousand other people who were just as confused — was that the joke flew right over their heads.

Allow us to explain. 

Watch: Tommy Little explain Thor. Post continues after video.

Little does not actually have a son, and the post — which was made in jest — was a reference to a moment in 2021 when the comedian was confronted during his stand-up tour by a woman he had previously dated, who was pregnant.

The radio star was halfway through his comedy routine when an audience member shouted aloud, "Why didn't you call me back?"

"I was like, 'I'm sorry?' She said, 'We went on a date and you never called me back. Oh, and I'm pregnant,'" Little recalled to Adelaide Now back in 2021.

He remembered the crowd falling silent for a few seconds, saying, "There was about five seconds of stunned silence in a room of more than 1,000 people."

Thankfully, the woman revealed it was a prank. Not the pregnancy part, or that she and Little had dated. Rather, she confirmed that he was not actually the father of her unborn child... AKA the kid he pretended to reveal to the world on Sunday.

"Then she starts laughing and says, 'Don't worry. It's not yours. We went on a date five years ago,'" he said. 

"Even though I knew it wasn't [mine], you do start to doubt everything you've done."

Tommy Little made reference to a prank from a 2021 comedy show. Image: Instagram @mrstommylittle.

While the woman in Little's pic is brunette, plenty of Little's fans shared their high hopes that his (blonde) radio co-host Carrie Bickmore would give him a "biological son". Even though they're, ya know, not together! But many fans do ship the pair, and think they have a genuine connection. The duo met in 2016 when Little joined The Project panel, with their hit drive show the Carrie & Tommy radio show launching a year later. And it's been a long-running joke that the pair are actually involved in a secret romance.

Before his... non-existent romance with Bickmore, the comedian dated environmental activist Natalie Kyriacou, with whom he split during COVID-19 lockdowns in Melbourne after a year together.

Tommy Little and Natalie Kyriacou. Image: Instagram @mrstommylitte.

He told TV Week at the time that the breakdown of his relationship devastated his mental health. 

"I was living with a partner but that didn't go well. She's wonderful but we didn't go well. Then I've been living with my housemate," he said, sharing that life locked inside was not nearly as productive or as promising as he hoped it might  be.

"... It sucked. I thought I was going to achieve so much, having more time on my hands, but I didn't. All I did was drink myself into a stupor," he confessed, adding that his "brain turned to mush".

"I didn't have any motivation to write stuff. My comedy is quite happy, you know. When a lot of that joy has been sucked out of that existence… I found it hard to be fun."

Feature Image: Instagram @mrstommylittle.