

Justin Timberlake stopped his concert to help a lucky fan make one of the biggest announcements of her life.

Timberlake rocked Detroit's Little Caesar Arena on Monday and in the middle of his show, he spotted fan Darcell Baxtresser -- who was on a girls night out -- holding a sign that read "Will you help me announce my pregnancy to my family?"

"This sign caught my eye, I gotta stop the show," JT said as he spotted it and snatched it up.

The singer lit up as he helped the mommy-to-be make the big announcement to her immediate family – and a packed arena. "Baby Baxtresser arriving November 1, 2018," the singer read aloud, and even gave the kid a catchy nickname: Baby Bax.

Darcell tells The Blast security initially told her there were no signs allowed. "[Security] was literally taking it out of my hands and I was like 'noooo, please, please!'" She eventually got the okay but was warned security inside the venue would probably take her sign – so she hid it underneath her shirt ... along with her tiny baby bump.

JT then proclaimed, "this deserves a toast" and walked off the stage to grab a platter full of shots, as he does. Of course, Darcell didn't get partake.

We're told the pregnancy announcement was a huge success. Darcell's family wasn't at the show but she immediately texted them a video and they "freaked out," naturally.

Congratulations ... looks like someone already has a Godfather!