The reality star was noticeably absent during the recently finished twelfth series of the ITV2 show, after taking time out to deal with personal issues.
And now, he's issued an apology to TOWIE's cast and crew, his family and friends, and his fanbase.
Mario told The Sun on Sunday: "After a few personal issues I went off the rails."
He admitted to "excessive partying over a three-month period" which had a negative effect on his health but now, he's taking care of himself and feeling better.
"I have been seeking professional assistance and am now fit and well. I hope that the producers and ITV will see my genuine remorse and consider allowing me to return to the show."
Mario hit the headlines earlier this year when The Sun claimed to have footage of him snorting a white powder during a night out. Mario did not address the allegation and no charges have been brought against him.
Shortly after TOWIE's latest series wrapped, Mario admitted on Twitter to feeling sad he hadn't been part of it.
"Gutted I couldn't be part of this series," he wrote, "but congratulations to the rest of the cast on completing series 12."
A show rep told us: "It was mutually agreed ahead of Marbella that Mario would take some time out from TOWIE to address some personal issues.
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