Gwen's ex stops her wedding!

Gavin’s making sure Gwen won’t be walking down the aisle to Blake anytime soon!

Gwen Stefani’s battle with her ex Gavin Rossdale has turned into a holy war!

As previously reported by NW, the Hollaback Girl has formally petitioned the Vatican to have her 13-year marriage to Gavin officially annulled, so she can tie the knot with country bumpkin beau Blake Shelton in a Catholic church.

However, Gavin is firmly blocking her Sweet Escape, with sources revealing the English muso is not too impressed about having their union wiped from the history books.

“Gwen’s biggest nightmare is coming true,” reveals a source close to the situation. “Gavin refuses to play ball.”

Gwen, 49, is devoutly religious and regularly attends church services with Blake and her three boys, Kingston, 13, Zuma, 10, and Apollo, five.