My, how they grow. Like his American clone, Justin Bieber, 18, the Australian answer to every young girl's prayers, Cody Simpson, 15, went with the muscle-shirt look at his Nevada Wild Fest performance, which will benefit the LIli Claire Foundation, at the Rio All Suite Hotel and Casino in Las Vegas.

Simpson and Bieber aren't oblivious to the comparisons made between them. In fact, they've embraced them, with Simpson teaming up with Bieber for certain performances on his Believe tour.

"Chicago shows tonight and tomorrow with @justinbieber," Simpson tweeted earlier this week before taking the stage with the Biebs.

WHO'S CUTER? Cody with younger brother, Tom / Credit: Brian To, WENN

And that's not all. Cody reportedly wants Bieber and his girlfriend, Selena Gomez, 20, to hang out with him and his not-quite-girlfriend, Kylie Jenner, reports Hollywood Life. "It’s awesome because the fans are beginning to see that we’re like a family almost; we’re all supporting each other. We’re a young dream team.” He also adores the Kardashians, Jenner's step-family — especially their constant press and tweeting about him, talking about how much he appreciates the "support of such a famous family."

Simpson will also join Bieber for the November leg of his tour. "Selena visits often and she's cool to chill with. Me and Justin like to do teenage stuff — we recently visited a haunted house which was so cool!” Simpson told the magazine.

Get Uinterview's FREE iPhone App For Daily News Updates here.

Get the FREE Uinterview iPad app here and watch our videos anywhere.

Check out Uinterview's exclusive with Cody Simpson here.

For more like this:

Aussie YouTube Sensation Cody Simpson Set To Tour With Big Time Rush

Shirtless Justin Bieber Reveals New Tattoo

L.A. Reid Announces Justin Bieber As New 'X Factor' Mentor

David Letterman Apologizes To Justin Bieber

VIDEO: Justin Bieber, Miley Cyrus Guest Host Ashton Kutcher's Punk'd

VIDEO: Justin Bieber Gets Fisker Karma For 18th Birthday

WATCH: Justin Bieber, The Wanted Perform On 'The Voice'

Emma Watson, Justin Bieber Have 'Most Influential' Haircuts Of 2011

Justin Bieber Denies Paternity Rumors

VIDEO: Justin Bieber Gets Birthday Kiss From Selena Gomez

Read more about: