Robert Irwin has whipped his fans into a frenzy by sharing a jaw-dropping photo which captured him flexing his bulging biceps while spending time with his niece.

The celebrity conservationist, 20, posted the adorable photo to Instagram on Friday, which showed him holding his sister Bindi Irwin's daughter Grace Warrior, three.

He was all smiles in the adorable photo as he flaunted his taut and bulging bicep while carefully holding his growing niece. 

Robert could not wipe the smile off his face as he cheekily hammed it up for the camera, and showed just how strong he is as he effortlessly held the youngster.

The reality TV star captioned the picture with some heartfelt words: 'Uncle life for me!'

Many of Robert's celebrity family and friends quickly took to the comment section to gush over the incredible photo. 

'Thank you for being the best uncle and brother. We love you!' wrote Grace's mother Bindi and family matriarch Terri Irwin added: 'Grace loves you so much!'

Meanwhile, The Wiggles star Lucia Field added: 'OMG there's no way she's grown up this much! whatttttt!!!' 

Bindi Irwin and her American wakeboarder husband Chandler Powell married on March 25, 2020 and welcomed their daughter Grace Warrior exactly one year later, on their first wedding anniversary.

Robert and Bindi are the children of  Steve 'The Crocodile Hunter' Irwin, who died age 44 off the coast of Queensland on 4 September 2006, after being pierced in the chest by a stingray while filming a nature documentary.

Bindi was six years old when he tragically passed, while Robert was three months shy of his third birthday.

His legacy, however, lives on through his family, who have continued his mission of wildlife conservation and advocacy, and there are reports that Grace will follow in her families footsteps when she gets older.

It was Steve's father, Bob, 85, who built the iconic Queensland zoo from the ground up in 1970 and passed it on to his late son and his wife Terri in 1992.

In his lifetime, Steve promoted wildlife conservation with his own hit TV show, The Crocodile Hunter.

His family have carried on his legacy with their own blockbuster wildlife reality series Crikey! It's the Irwins, which debuted in 2018 and can still be seen on the Animal Planet network.