Kim Kardashian posts rare photo with brother Rob and fans are making the same comment

Kim Kardashian has posted a super rare photo with her younger brother, Rob Kardashian, and it's clear that fans have all had the exact same reaction to the selfies.

The 44-year-old took to Instagram on Wednesday (25 June) to share a series of snaps with her 356 million followers a birthday post for LaLa Anthony, who she dubbed her 'best friend'.

She captioned the snap: "Happy Birthday to my ace @lala Truly the bestest best friend a girl could ask for! I love you so much!!!! Today’s your day!"

But it wasn't Kim nor LaLa that fans were obsessing over.

Nope, it was the appearance of 38-year-old Rob - the youngest of the Kardashian siblings, bar their half-sisters Kendall and Kylie Jenner - who doesn't have make as many public or social media appearances as his older sisters.

Kim Kardashian has just posted a snap with her little bro, Rob, and fans are loving it (Gilbert Flores / Contributor / Getty Images)

One Instagram user quipped: "Rob is starting to look like his early 2000 self again."

"Rob still handsome," gushed a second while a third chimed in: "ROBBBBBBB. HEY GIRLS BUT ROBBBBBB!"

A fourth beamed: "Aww Rob cameo."

"OH MY GOSH ROBERT!!!!!!!!!!!!" exclaimed a fifth while a sixth penned: "We missed Rob!"

Another echoed: "Everyone just hyped Rob is in the photo!"

"Sorry but Rob stole the show in this photo," praised a final Instagram user.

Fans were gushing over Rob's rare cameo on his big sister's social media (Instagram/@kimkardashian)

While Rob features in all of his sisters' Instagram posts every now and then, it would appear that he and 40-year-old Khloé - who he is the nearest in age to - are the closest.

In April of this year, Khloé revealed in her new podcast Khloé in Wonder Land the nickname she has for her younger brother, whom she said 'loves to be a little elusive'.

"I call him the Wizard, from The Wizard of Oz, cause he likes to be behind the curtain," she explained.

And, back in December, she opened up to Bustle about their relationship together, noting that she can 'identify with him' on a different level than with her sisters.

"I feel so deeply what he feels - the struggles that he has, or just wanting to be out of the public eye, or just feeling like he doesn’t fit in or is being judged about his appearance," she said.

"I feel like we were raised in pairs: It was Kourtney and Kim, and then it was me and Rob, and then Kendall and Kylie," Khloé continued. "And I just feel like we are both each other’s protectors. I love him so much. It’s just innate."