Britney Spears has sent her congratulations to her younger sister Jamie Lynn after the singer gave birth to her second daughter.

Baby Ivey Joan Watson is her first child with husband Jamie Watson.

Pregnant + shopping = not my best idea 🤰🏼🐷😓

A post shared by Jamie Lynn Spears (@jamielynnspears) on

Jamie Lynn is already a mother to nine-year-old Maddie Briann from a previous relationship.

Britney wrote on Twitter: “I could not be more excited to welcome baby Ivey to this world. Congrats to @jamielynnspears and the whole family – I love you all so much!!!”

Jamie Lynn previously announced the news of the arrival on Twitter, writing: “Baby Ivey Joan Watson is here,” along with a red heart emoji.

She confirmed her pregnancy on Christmas Eve when she wrote on Instagram: “Looks like we are starting off 2018 with another big milestone…sooo happy to announce that Maddie is FINALLY going to be a big sister.

“2017 was filled with some of the biggest challenges of my life, as well as some of the biggest blessings, so I made a choice to lay low this year to focus on truly becoming my best self as a person and as an artist.

Looks like we are starting off 2018 with another big milestone…sooo happy to announce that Maddie is FINALLY going to be a big sister👶🏼2017 was filled with some of the biggest challenges of my life, as well as some of the biggest blessings, so I made a choice to lay low this year to focus on truly becoming my best self as a person and as an artist. During that time, I continued working on my music and telling my story, which has created some of my most honest work and I CANT wait to share that with you all very soon. 2018 is going to be filled with many milestones both personally and professionally. I appreciate each of you for your patience and support through it­ all. 2018 has a lot coming, so GET READY…….. #12DaysofJLS

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“During that time, I continued working on my music and telling my story, which has created some of my most honest work and I CANT wait to share that with you all very soon. 2018 is going to be filled with many milestones both personally and professionally.”

Britney is also a mother to two children – sons Sean Preston and Jayden James with ex-husband Kevin Federline.