Bindi Irwin and Chandler Powell reveal they're having a baby girl: 'You are our world'

Their first child together is due in 2021.

Bindi Irwin and Chandler Powell are having a baby girl!

The couple revealed the sex of their first child together on social media Tuesday, with Irwin, 22, sharing a fun animal fact alongside her pregnancy update.

"Baby girl, you are our world," she wrote. "Our beautiful daughter is now about the same size as a hatchling Aldabra tortoise and is as healthy as can be. We can’t wait for her arrival next year."

The photo, which was also shared by Powell, 23, shows the pair holding an ultrasound as they pose with one of Australia Zoo's shelled reptiles.

"Our little girl and my beautiful wife are my entire world," he wrote. "I’m so excited to meet our daughter when she’s born next year and to see the incredible person she will grow up to be."

Irwin and Powell first announced they were expecting a bundle of joy on Aug. 11, writing that they had a "Baby Wildlife Warrior" due 2021.

Earlier this month, Irwin told fans her baby was "about the size of a hummingbird."

Powell and Irwin, whose father is late "Crocodile Hunter" star Steve Irwin, married March 25 in a small ceremony at the Australia Zoo. Irwin's mom, Terri Irwin, and brother, Robert Irwin, were in attendance.