The ITV1 daytime chatshow had invited The Script frontman to join its panel for a chat about the new BBC One talent contest, which features himself, Tom Jones, Jessie J and will.i.am as 'coaches'.
But according to The Sun, Britain's Got Talent bosses had Alesha added to the bill of the same episode when they got wind of the plan, fearing a solo appearance from Danny would give its arch rival too much publicity.
A source told the paper: "It really is war now. Where The Voice goes, BGT is lurking in the shadows. It would be funny if it wasn't so ridiculous."
It is the latest clash in an all-out war between the two shows, which will overlap for twenty minutes when their first episodes air this Saturday.
Alesha and Danny will be on Loose Women this Friday at 12.30pm on ITV1.