(CNN) New Zealand Prime Minister Jacinda Ardern gave birth to a baby girl Thursday, the first world leader in nearly 30 years to have a child while in office.
In a post on her official Instagram account, Ardern said the baby arrived at 4.45 pm local time, weight 3.31 kilograms (7.3 pounds).
"Thank you so much for your best wishes and your kindness. We're all doing really well thanks to the wonderful team at Auckland City Hospital," she said in her post.
Admitted to the hospital earlier in the day, Ardern's expected due date had been June 17.
Excitement and anticipation had been building over the last few days, with many media outlets setting up live blogs to track the latest developments.
Jessie Chiang, a New Zealand Radio reporter, tweeted that she and other journalists had been at the hospital since 6 a.m.
"No baby yet...but they are feeding the media," she wrote.
Another outlet even put together a baby-themed playlist to "help bring her bub into the world."
New Zealanders also speculated over the baby's gender and name. One Twitter user joked on Thursday, "If it's a boy I'm going with Winston Michael Joseph Peter Norman David David David Phillip Andrew Gayford Ardern."
However, the baby has a higher chance of being named Oliver or Jack -- the two most common baby boy names of 2017. If it's a girl, it might be Charlotte or Harper, the most common girl names.
Maternity shop Baby Belly also joined the fun, tweeting, "Let us know your pick for either a boy or girl & the weight and the closest guess will win a $50 voucher to spend with us!!"
Twitter users were quick to point out that if born on Thursday, the baby would share a birthday with Prince William and former Pakistani Prime Minister Benazir Bhutto, who was the first and (until now) only leader to have a baby while in office, in 1990.
Bhutto's daughter, Bakhtawar Bhutto, issued congratulations to Ardern via Twitter.
"Congratulations to Prime Minister @jacindaardern on the wonderful news," she wrote.
The 37-year-old prime minister, who was elected in October, announced her pregnancy in January via Instagram.
"Clarke and I are really excited that in June our team will expand from two to three, and that we'll be joining the many parents out there who wear two hats," Ardern said in the post.
Her partner, Clarke Gayford, hosts a fishing documentary series, but will give that up to be a stay-at-home dad.
Ardern has fielded several questions about whether she wanted children, but has told media outlets that she should not have to respond to such an inquiry.
"I totally accept that I will be asked that question because I chose to be honest about it," Ardern said on "The AM Show," a New Zealand radio program. "I think a lot of women face this dilemma in the workplace, no matter what their profession or job might be."
In an interview with Radio New Zealand, she said, "I am not the first woman to multitask. I am not the first woman to work and have a baby; there are many women who have done this before."
Ardern became her party's youngest leader and New Zealand's youngest in 150 years after defeating former Prime Minister Bill English in last October's election. It marked the first victory for the Labour Party in nine years. She led the group for three months before being elected Prime Minister.
Deputy Prime Minister Winston Peters will fill in for Ardern while she is on parental leave for six weeks.