The Daily Mail claims the pop star will marry her partner Formula 1 team boss Christian Horner at Syon House, home of the Duke of Northumberland.
It's thought Revd Gumbel will preside over the service after he became good friends with the ex-Spice Girl 12 years ago.
The pair were said to have met at one of his Alpha courses.
Revd Gumbel is the vicar at Holy Trinity, Brompton, in central London and is known across the Christian faith.
Halliwell is one of several famous faces who have taken the course which introduces people to Christianity.