"Lesson 1: When dad bottle-feeding express milk for the first time don't get over-excited and feed her too much," he wrote, with a picture of his white shirt covered in milk spit-up.
The Purple wiggle, who was previously married to fellow Wiggle's member Emma, surprised fans over the weekend when he announced the birth of his daughters on social media.
The Purple Wiggle shared the photo to his Instagram stories. Photo: Instagram
"Oh Lulu and Lottie, your mummy and daddy love you with all we have," the 34-year-old captioned the photo of him, Dana and their newborns.
You are both so beautiful – and I would love to sing to you both forever."
Stephenson, also 34, proposed to Lachy in April this year, with some help from her son Jasper from a previous relationship.
"On Thursday night, Dana asked me to marry her at home under a fairy light sky and a very excited little boy in a beautiful bow tie," Lachy posted to Instagram after she popped the question.
"A room filled with the most incredible flowers and Lachy singing at his piano and then asking me to marry him. It was such a surprise and so special. Our faces say it all,"
Stephensen, a ballet dancer, posted her own Instagram post, revealing Gillespie was actually the first to pop "the special question", but she also wanted the opportunity to do so.
"It was something very meaningful for us to both have the opportunity to propose to one another, each in our own way," she wrote on Instagram.
"Last week, with the most beautiful (and excited!) little boy by my side in a special bow tie, it was our time to ask Lachy our special question - and it was so, so wonderful."
We can't wait for some wiggly updates on how the couple is adjusting to being a family of five!