Brandon Jenner and his wife Cayley have welcomed their third child into the world

Sharing details of the birth, they shared that the newborn weighed just over 9 lbs and gushed that she's a "perfect little peanut".

The parents wrote alongside a snap of the little one: "She's here.

"Joan Almond Jenner. Named after Cayley's beloved grandma (Joanie).

"Born at home in a flash, just the most amazing experience for mama and baby girl. A beautiful, gentle birth. 9 lbs 2 oz, 21 1/2 inches long. Perfect little peanut, we couldn't be more in love. And the kids are absolutely thrilled to have a baby sister. Welcome to our world, sweet baby love."

Grandma Linda Thompson - who had Brandon and Brody Jenner, 41, with Caitlyn Jenner - gushed in the comments: "Crying... Already obsessed... Such a blessing! And such a beautiful tribute to the wonderful matriarch Joan Almond! My family means absolutely everything to me! Congratulations on bringing more love into this world. I love y'all so much."

Following his parents' split and Caitlyn's marriage to Kris Jenner in 1991, Brandon and Brody gained stepsiblings Kim, Kourtney, Khloé and Rob Kardashian.

Kris and Caitlyn also had daughters Kylie and Kendall Jenner together and Caitlyn has children Cassandra Marino and Burt Jenner with first wife Chrystie Scott, so Brandon has plenty of experience when dealing with a blended family.

He recently told Us Weekly: "I think that it's really good to watch peers and try to be somewhere in the middle. A good rule of thumb is [to be] not the first [and] not the last to get to anything."

Brandon wants his children to get to know their extended family.

He said: "They've met [Kylie's kids], but we haven't spent that much time [together] recently. We're just all super busy. You have the intention where you're just like, 'Yeah, let's do this.'"

Brandon also revealed that his kids spend a lot of time with Caitlyn, 74.

He said he is now "very close" with his dad and revealed the pair talk "almost every day".