Duchess Catherine will still "play a part" in her sister's wedding.
Duchess Catherine
The 34-year-old royal - who is married to Prince William has reportedly decided not to be a bridesmaid or maid of honour when Pippa Middleton ties the knot with James Matthews next May because she doesn't want to upstage the bride, but insiders insist that doesn't mean she will be stepping back from proceedings altogether.
A source told Britain's HELLO! magazine: "There have been ludicrous reports suggesting that Catherine is barred from the wedding - nothing could be further from the truth.
"It is ridiculous to suggest she will not play a part in the day."
However, the duchess will be represented in the bridal party by her children, as Princess Charlotte, 19 months, is expected to be a flower girl and three-year-old Prince George will be a page boy.
It has been reported Pippa and James will marry on May 20 next year, but there is no "particular significance" to the date they have chosen.
A source said: "There is no particular significance with 20 May - it is just the date they have decided on."
The couple will marry at St. Mark's church in Englefield, before a reception in the grounds of Pippa's parents home in nearby Bucklebury.
And the party planner chose the venue because it is both pretty and discreet.
The source said: "Pippa is a traditional girl and wanted to marry close to home.
"They appreciate that there will be significant interest with the wedding but want to keep it as private as possible.
"After the service, guests will head to the Middleton home for a reception."
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