At 34, the multimillionaire property investor took to Instagram on Wednesday to post a heartwarming series of photos, showing the tender moments he shared while holding his newborn son.
In one particularly charming photo, a shirtless Portelli is seen smiling warmly at the camera, seated with the baby peacefully in his arms. Another image captures the pure joy on his face as he gazes at his child.
"Welcome to the world little man," Portelli captioned the photos, though he chose not to reveal the baby's name.
The exciting news quickly attracted congratulations from many of Adrian's celebrity friends, who were eager to share in his joy.
Controversial The Block bidder Adrian 'Mr Lambo' Portelli (pictured) welcomed his first child with girlfriend Karlie Butler on Monday
The Block 2022 winners Omar and Oz both posted love heart emojis and influencer Mitch Orvall wrote: 'Congrats brother'.
Portelli told the Herald Sun he was over the moon at becoming a first time father.
'He was four days over. It's an amazing, overwhelming experience,' he said.
The millionaire property investor, 34, took to Instagram on Wednesday to share a loved-up gallery of photos showing him tenderly cradling his newborn son
In November, Portelli threw a lavish baby shower for his pregnant partner Karlie.
He shared some photos on Instagram of the bash, which showed him posing with blue baby blocks and blue balloons.
Another was of the very expensive push present he bought his partner - a luxury $300,000 Aston Martin sports SUV.
Portelli and his girlfriend Karlie Butler (pictured) announced on social media in September they were expecting their first child
'Push prezzie well deserved for putting up with me,' he wrote next to the photo.
In September, Portelli hosted an elaborate gender reveal ahead of the birth of his first child.
The couple held the gender reveal at his $39 million penthouse in East Melbourne.
Portelli is a multi-millionaire property investor and online promotions guru with an estimated net worth of $350million.
'Welcome to the world little man,' Portelli wrote next to the photos