The Phoenix Mercury point guard surprised everyone on Monday by posting photos of her pregnant belly on Instagram.

"New addition loading 🧡," the 32-year-old said in the caption.

This isn't Diggins-Smith's first blessing ... remember, the 6-time WNBA All-Star played the entire 2018 season while pregnant with her first child -- when she was with the Dallas Wings.

Skylar and her husband, former Notre Dame receiver Daniel Smith, hid her pregnancy from everyone -- saying back in October 2019 via Twitter, "I played the ENTIRE season pregnant last year!"

"All-star, and led league (top 3-5) in MPG....didn’t tell a soul."

Diggins-Smith opted out of the 2019 season after giving birth to her son that April due to postpartum depression ... and she's been public about not receiving the necessary help from her team.

"Having no support from your own organization is unfortunate," Diggins said.

"People called me a quitter, said I gave up on my team, etc., etc. Not knowing I took two FULL months away from everything because of postpartum depression."

Diggins-Smith added, "With limited resources to help me be successful mentally/physically. But just wait though....KEEP THAT SAME ENERGY."

Of course, Diggins-Smith ended up with the Phoenix Mercury after a sign-and-trade deal in February 2020 ... and has been a key player since.

In the last two years, Diggins-Smith -- the 3rd overall pick in the 2013 WNBA Draft -- averaged 17.7 points, 4.7 assists, and 3.2 rebounds per game, making the playoffs in both seasons.