Don't expect everyone at the Kardashian-Humphries wedding to be perfectly behaved!

The bride-to-be's stepbrother, Brody Jenner, is planning on letting loose during Kim Kardashian and Kris Humphries' celebrations Saturday night. (Brody's father, Bruce, has been married to Kim's mom, Kris, since 1991.)

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"Getting a nice 10K run in before the long drive up to the wedding," the 27-year-old former Bromance star tweeted Saturday. "Congrats, Kim. Love you." 

But Brody -- who has been romantically linked to Avril Lavigne since 2010 -- alluded to his partying plans for Saturday night. "Oh yeah," he added. "And it's my birthday at midnight. RAGING tonight!"

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Kim's brother Rob also seemed up for some fun. He retweeted Brody's tweet, adding, "I'm with Bruce tonight and we are gonna RAGE!!!"

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Humphries, 26, joked with his future brother-in-law earlier about whether he should go with a "mustache or no mustache for the wedding?"

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Rob's advice for the NBA star? "Get a hair cut and shave your mustache," he said.

Kim, 30, will probably appreciate a clean-shaven beau. Her pre-wedding rituals? "Spray tanning, nails, a midnight call to Anastasia to do my eyebrows," she told Ryan Seacrest Friday, adding that she feels completely "calm" about her upcoming "I do's."

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