Rob Kardashian who turns 25 today, hit Sin City this weekend to celebrate with big sister Kim Kardashian, mom Kris Jenner and younger sisters Kendall and Kylie Jenner.

“Let the festivities begin,” Kim tweeted Friday, along with a photo of her, Rob, Kylie and Kendall in their hotel room before the shindig.

“Can’t wait to see what everyone in #vegas is talking about. @1OAKlv for my birthday celebration tonight!,” Rob chimed in early Friday.

Kim and Kris continued the party with the birthday boy at the Las Vegas hotel’s 1 OAK Nightclub, where he was treated to a colorful tiered cake created by chef Jean Philippe.

And although Khloé and Kourtney missed Rob’s birthday celebration, they made sure to show their love for their baby bro via Twitter.

“Happy Birthday to my brother @RobKardashian wooohoooooo,” Khloé tweeted Saturday.

Kourtney also gave Rob a shout-out, writing “Happy Birthday to my favorite brother @RobKardashian!! Missed you guys last night! I love you so much. Come over for some cinnamon booty!”

Happy 25th birthday, Rob!

Rob Kardashian birthday