The fitness guru garnered a large following after openly sharing and talking about her pregnancy workouts.
And just hours after twins Evie Mae and Aria Joy were born, Guidolin, 26, set up an Instagram account for them. They now have 25,000 followers.
On 31 August, Guidolin uploaded a photo to the twins' new Instagram account and wrote: "Welcome to the world Evie & Aria #twingirls."
Guidolin then took to her own Instagram account, telling her 200,000 followers she was in a complete "newborn love bubble".
She wrote: "Introducing @evie_and_aria both almost 5 pounds, healthy and beautiful baby girls.
"I am in absolute awe of my body, the creations we made and the incredible love my heart is filled with. Thank you for all of your well wishes! 😘"
The weightlifter, who is married to bodybuilder Nathan Wallace, hasn't shied away from keeping her fans updated in the first 24 hours of their lives.
She later told her fans she was sending off her twins' placentas for DNA testing to confirm whether or not they are identical, as well as giving a preview of their nursery.
She added: "At this stage they look like they are identical, although won't be able to 100% confirm for a couple of weeks."
Guidolin's fitness regime was met with criticism after she uploaded photos of herself weightlifting at 26 weeks pregnant.
At the time, she told HuffPost UK Parents: "I certainly don’t push myself – I believe in listening to your body and if I want to rest for the day I will.
"My doctor and obstetrician are both happy and I’m always guided by my husband Nathan (a strength and conditioning coach) – that is good enough for me."
Guidolin continued: "The negative comments, I believe, come out of fear and myths or old wives' tales that women cannot do any exercise while pregnant - even when medical professionals are pushing for women to remain active."
She said she was motivated to remain active with this pregnancy, because her previous two pregnancies resulted in gestational diabetes.
She added: "I had 10lb babies and needed severe interventions to deliver as I was simply not strong enough, so I wanted to make a positive change this time."