Robert and Bindi Irwin appear to be two of the best of friends, but it appears as though the siblings may have a slight rivalry.
New Idea reports Robert, 18, is apparently jealous after Bindi, 24, scored a role in a Marvel animated series.
While this doesn't sound like something you'd expect from the Irwin siblings, the source claimed, "It came as a bit of a rude shock that Bindi is still seen as the more bankable star largely because of the huge amounts of press she’s generated."
Apparently, Robert had hoped he would be attracting some Hollywood attention thanks to his buff physique and animal escapades.
"Robert is single-minded. He spends hours in the gym, networks like a champion, and is seen as very much a real-life superhero," they added.
However, it doesn't appear that there's any bad blood between the pair, and Robert is said to be Bindi's "biggest fan". Phew!
Bindi shared the exciting announcement on Instagram earlier this month, revealing she'd recorded a voice-over for her role as Isla Coralton, an oceanographer, in an episode of Spidey and His Amazing Friends.
The animated show features younger versions of fan favourite Marvel characters and airs on Disney Junior.
Bindi shared that it's "an honour" to be chosen for the role, writing on Instagram, "Being an enormous Marvel fan, it is an honour to be part of the extraordinary world of Spidey and his Amazing Friends."
Robert has also previously voiced a character, playing Alfie in the children's series Bluey.
Robert's tribute to Bindi
The Irwin siblings are known to get along very well with Robert sharing a sweet tribute to his sister for her birthday earlier this year.
"Thanks for being someone I can always count on for advice, support, kindness and a good laugh," he wrote. "Bindi you are an absolute boss! Hard worker, amazing sister and such a wonderful mum to Grace, she is a lucky kid! Love you."
"Your father would be so proud of both of you," one follower wrote.
"Such a beautiful message - what awesome siblings you are," another added.
Bindi has also described Robert as an "awesome uncle" to her daughter Grace, adding, "Thank you for being the best. Love you so much and beyond proud of you."
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