The four year old, who underwent Car–T therapy at the Children's Hospital of Philadelphia after an incredible £500,000 public fundraising campaign, is currently in remission from Acute Lymphoblastic Leukaemia.
In news to warm the hearts of Zac's supporters across the country the Broseley youngster started doing half days at school on Monday, and his mother, Hannah Oliver-Willets said he has "loved" being back.
Writing on the Facebook page set up to update supporters on her son's progress she said: "Zac started doing half days at school on Monday, which he loves. His appetite is amazing. In fact his appetite is better than amazing, it's huge.
"We have started getting into a routine and have begun to introduce some structure to our days.
"This is a very satisfying feeling because we haven't had any for such a long time due to Zac being poorly."
Earlier this month Zac was able to reveal to the world that he was cancer free after the specialist treatment, which was unavailable on the NHS.
Back to Philadelphia
Hannah explained how Zac is now waiting for treatment for an inguinal hernia, and Perthes disease in his hip, and will be returning to Philadelphia for a check up on his cancer next month.
She said: "We are due to fly back out to the USA around the end of April for Zac to have a bone marrow biopsy, three bone marrow aspirations and a lumbar puncture.
"This is a big test again to check that he is still cancer free."
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- Tears and relief as poorly Zac, 4, starts his treatment in America
Hannah has also used her post to encourage people to take stock of their lives and try to make sure they have no regrets.
She said: "This journey has made me stop and realise just how precious life is. You really don't know what is round the next corner.
"I truly think everyone should write a bucket list to make sure dreams are fulfilled and regrets are something of the past.
"It's never too late to make changes or take the plunge into something you've always wanted to do but never had the chance or time to do.
"There is always time, until that time has been taken away from you like cancer does. Then you will regret you never had the time."