Nikki Sixx and wife Courtney Bingham Sixx have welcomed a new member of their crew.

The Mötley Crüe bandleader and the fashion model announced the arrival of their bundle of joy on Instagram Wednesday.

Nikki and Courtney attend the Premiere Of Netflix's "The Dirt" on March 18, 2019 in Hollywood, Calif. (Photo by Paul Archuleta/FilmMagic)

"Saturday night my wife Courtney and I welcomed into our world and family a very beautiful baby girl named Ruby Sixx," the proud papa beamed. " A spunky little girl with a full head of hair making her the 5th Sixx joining her two sisters and two brothers."

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Sixx has four children from previous relationships with former Playboy Playmate Brandi Brandt and actress Donna D'Errico.

(Photo by Paul Archuleta/FilmMagic)

"Fatherhood has been the greatest joy in my life.....and @how2girl is a real natural as a mom," Sixx continued. "I would like to thank our family and friends for all the love and support ( and flowers)."

The former heavy metal madman-turned-family man is starting his daughter out on a musical path already.

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"We are already sleep training her with a metronome and I got her a pink bass," he wrote.

Courtney Sixx, Nikki Sixx and family attend the premiere of Netflix's 'The Dirt" at the Arclight Hollywood on March 18, 2019 in Hollywood, California. (Photo by Rachel Murray/Getty Images for Netflix)

Sixx had a vasectomy years ago and reportedly used a sperm harvesting method and artificial insemination instead of a reverse vasectomy in order to father his fifth child.

Bingham and Sixx got married in 2014. This is her first child.