Alanis Morissette is a mum again.

The Ironic singer has given birth to her third child, son Winter Mercy Morissette-Treadway.

Alanis shared the happy news via Instagram on Monday, posting a sweet photo of the baby, who was born on Thursday.

"He's here! Winter Mercy Morissette-Treadway. #8/8/19 #mywholelifeidreamedoflovingyouthree," the singer captioned the shot.

Little Winter joins sister Onyx, who is nearly three, and brother Ever, eight - Alanis's kids with rapper husband Mario Treadway.

She recently made it clear she is urging family and friends to help her through postpartum depression if she experiences it for the third time after experiencing drastic mood swings following the births of her two kids.

"I had postpartum depression both times, which basically feels like tar had taken over my whole body and I was underwater...," she told SELF magazine. "First time around, I didn't seek help for a year and four months and then second time around, I waited four months.

"This time around I'm not waiting even four minutes, I'm just gonna be like, 'OK, everybody, even if I say I'm OK, I want you to resist believing me at first.' I'm actually gonna need support and I'm not gonna push it away."

The star had a great pregnancy, adding, "I'm one of those women that actually really enjoys being pregnant... Even when I'm just sitting still I feel productive; I'm still building a human being, which still boggles my mind."