ITV and All Star Family Fortunes presenter Kay mutually decided to part ways after feeling that a comic would better suit the format of the show.
Now Lemon, real name Leigh Francis, will present the gameshow alongside I'm A Celebrity... Get Me Out Of Here winner Stacey Solomon.
"The tone took us by surprise a little - there was much more mayhem than we expected and we felt that a comedian would be best suited to host the show," an ITV insider added.
Meanwhile, Kay explained of the situation: "Following the pilot, the producers and I sat down and talked about the tone of the show. We all agreed that because of the mix of comedy and slapstick challenges that it would benefit from having a comedian host it. I'm really happy with the decision."
Sing If You Can represents the first primetime ITV1 project for Lemon, who is best known for ITV2 ratings-powerhouse Celebrity Juice.
Celebrities who are confirmed for the show include musicians like Jedward, Chesney Hawkes, Boyzone's Mikey Graham, Ray Quinn, Camilla Kerslake, Jonathan Ansell, Toyah, Sinitta, Steps star Faye Tozer, Michelle Gayle and Brenda Edwards.