Rob Kardashian is very happy for his sister Kim Kardashian's pregnancy news -- but he won't be following in her footsteps.

The Keeping Up with the Kardashians starlet, 32, revealed Dec. 30 that she's expecting her first child with her boyfriend of eight months, Kanye West.

PHOTOS: Why Kim and Kanye are the perfect match

"It's beautiful. It's a blessing," Rob, 25, told E! News of Kim's pregnancy. "The new year, we've got another child coming, so that's great. Kim's never had a baby, so it's going to be a beautiful blessing."

Like her older sister Kourtney Kardashian, who shares son Mason, 3, and daughter Penelope, 5 months, with longtime boyfriend Scott Disick, Kim is having a baby before marriage. Rob, however, says he won't be doing the same!

"You gotta be married first," he said. "That's my rule: marriage then baby!"

PHOTOS: Kim and Kanye's sweetest moments

Married or not, Kim has two excited aunts-to-be in sisters Kourtney and Khloe.

"Been wanting to shout from the rooftops with joy and now I can!" Kourtney tweeted after West, 35, announced Kim was pregnant with his baby during a concert at Atlantic City's Revel Resort. "Another angel to welcome to our family. Overwhelmed with excitement!"

PHOTOS: Kardashian family album

Khloe also tweeted, "Keeping secrets is hard with so many family members! Especially when you are so freaking excited! Love is everything!"

This article originally appeared on Rob Kardashian Calls Sister Kim Kardashian's Pregnancy a "Beautiful Blessing"