The pair were said to have ditched their dates with members of the public in favour of one another during the most recent series.
The Daily Mail reported that the couple were getting "cosy" during filming of the show's finale at Cape Verde, which aired last week.
"There is clearly something going on behind the scenes between Tallia and ‘Muggy’ Mike," an insider said. "They were cosy on many occasions, sneaking off to the beach together and even spotted sitting together on the long haul flight home from Cape Verde."
The insider added: "He seemed very protective of her and not his usual Muggy self."
Tallia turned up to the final evening alone after ditching her original date she had met on the show.
But the singer insisted she and Mike had never got together.
"The thing about me and Muggy is he's more of a big brother to me," Tallia told Pretty52 this week. "Everything was completely taken out of context. He was like a big brother and he had my back, it wasn't like a romantic friendship.
"At the time we were just getting on so well we were like brother and sister, we were just so close with each other which was lovely, but it definitely wasn't romantic in any sense. It was just like a great friendship."
She added: "As a cast we all got along really well with each other and it was just a lovely environment to just be in. I feel as if the public could really tell that we were all genuinely friends and getting along with other."
While Mike and Tallia may have not got together, in the past Celebs Go Dating's stars have fallen for one another.
However neither relationship lasted, both ending on rather messy terms.
Alongside Tallia on the Celebs Go Dating 2018 line up are Hollywood's Jonathan Lipnicki, double Olympic gold medallist Jade Jones, Made In Chelsea's Ollie Locke and comedian London Hughes.
Rounding off the cast are Love Island's Muggy Mike, TOWIE's Gemma Collins and MiC's Sam Thompson.
Celebs Go Dating 2018 aired earlier this year on E4.
It's expected that the show will return with a fifth series.