Watch Beyoncé's twins Rumi and Sir make a rare appearance with older sister Blue Ivy in their mom's latest Ivy Park ad

• Beyoncé's children Blue Ivy, Rumi, and Sir appear in her new Ivy Park campaign, released Wednesday.
• They model the singer's latest collaboration with Adidas, which features kids' clothing.
• "The rodeo isn't just for the grown ups," the Ivy Park account wrote on Instagram.

Beyoncé's latest Ivy Park collaboration with Adidas features children's clothing, and she tapped her own three kids to model the rodeo-themed line.

In a campaign video released on Wednesday, the Houston-born singer poses with her 4-year-old twins Rumi and Sir in the center of a horse corral, all three of them donning blue ensembles. She later walks hand-in-hand with her daughter Blue Ivy, matching the 9-year-old in brown and purple cow-print leggings.

"The rodeo isn't just for the grown ups. Introducing IVY PARK Kids," the brand's Instagram account captioned the advertisement.

The collection will become available online on August 19.

Beyoncé, who shares Blue Ivy, Rumi, and Sir with her husband Jay-Z, recently told Harper's Bazaar that the inclusion of a children's line in the Ivy Park brand has been a long time coming. Her own family, she explained, served as a major inspiration.

"I'm excited that IVY PARK x adidas will now feature kids' clothing with this drop. On our family vacations, we love to coordinate our outfits," she said.

The Grammy-winning pop star continued: "My kids are usually on set with me for shoots, and we'd find ourselves putting them in extra-extra-smalls so we could match. So, it is a natural progression for IVY PARK to introduce a selection of key silhouettes in children's sizing."

By the time Blue Ivy made a cameo in her mom's rodeo-themed promotional video, she had already proven her affinity for modeling.

In February, the eldest Carter child, who already has her own Grammy win under her belt, popped up in Ivy Park's advertisement for a collection called "Icy Park."

According to Beyoncé's mother Tina Knowles, her 9-year-old granddaughter "inserted herself" into the photo shoot.

"She was not supposed to be in it ! She was just hanging out and got dressed and I guess she said 'I'm not gonna tell you what I could do I'm gonna show you,'" she wrote, adding, "I love that aggressive spirit My Blue Blue!!!!"