Purple Wiggle Lachy Gillespi was unable to contain his joy as his fiancee Dana Stephensen gave birth to twin girls.

He announced the safe arrival of his twin daughters with an unexpected but exciting Instagram post.

The proud parents can be seen holding Lulu and Lottie, looking on in awe.

"Oh Lulu and Lottie, your mummy and daddy love you with all we have - you are both so beautiful - and I would love to sing to you both forever......... 🌈💜💜🌈," Lachy wrote.

Meanwhile Dana posted the same photo on Saturday morning and mused: "Lulu and Lottie - our two little sweethearts 💕💕."

Fans were surprised by the news, as there is no mention of Dana's pregnancy on her Instagram, but the surprise announcement was met with well-wishes from Lachy's bandmates, including ex-wife Emma Watkins.

"So beautiful. Congratulations ❤️," Red Wiggle Simon Pryce said.

"Welcome to the world! 💜💜," The Wiggles' band account wrote.

The happy couple never publicly announced the pregnancy, and the pair's romance was first confirmed in August last year.

Dana shared with The Daily Telegraph just how she was feeling about Lachy.

"He's just amazing and I just love him so much."