It's official, "Mad Men" actress Jessica Paré brough her baby into the world over the weekend. On March 21, her boyfriend John Kastner announced their newborn son's arrival initially over Instagram, and then on other social media sites.

In the photo posted by Kastner, it shows his daughter Summer Lee, age 8, holding her baby brother. The Quebec native captioned the photo, "Please meet Blues Anthony Paré Kastner..." Summer shows an innocent and proud-sibling smile while her brother looks peaceful, swaddled in a comfy blanket.

Paré, who is also Canadian, had kept her pregnancy a secret until October of last year when her rep confirmed many suspicions. Around the same time, the couple had posted a photo announcing their pregnancy.

The Instagram photo showed Kastner and Paré in a loving embrace in the background, enjoying the weather while Summer took center stage again, sporting an adorable shirt with owls on it while the shirt read, "I'm going to be a big sister."

For those that many not know, Kastner was formerly married to Nicole de Boer. Paré and Kastner have been dating for two years, and Kastner is the front man for the Canadian punk back Axwell. Paré is most known for her current role as Megan Draper in AMC's hit series "Mad Men."

The series also stars John Hamm as Don Draper, Elizabeth Moss as Peggy Olson, Vincent Kartheiser as Pete Campbell, January Jones as Betty Francis, Christina Hendricks as Joan Harris, Aaron Staton as Ken Cosgrove, Rich Sommer as Harry Crane, John Slattery as Roger Sterling, Kiernan Shipka as Sally Draper and Robert Morse as Bertram Cooper.

The final season of "Mad Men" premieres on April 5 with only seven episodes left.