Bernie McKenna was nominated by the Lord Lieutenant of Tyrone for her work with Castlecaulfield Horticultural Society, which has enjoyed local and international success after it was recognised at last year's Communities in Bloom competition in Canada. The village has previously picked up awards for the Ulster in Bloom and Britain in Bloom titles.
The group, which has around 40 members, is co-chaired by Mrs McKenna and Bob McClure and includes friends from both sides of the community.
She will be among a crowd of 1,200 community leaders and young people who have shown strong leadership invited to watch the arrivals of the bride and groom as they enter and leave Windsor Castle.
She will be accompanied by her husband Eugene to watch the proceedings from the exclusive spot.
Bernie said: "I had no idea this was going to happen.
"I was in the hairdressers with no glasses on when I got the email, so it was a bit of pandemonium.
"I couldn't believe it so I rang Eugene and he couldn't believe it either," she said.
"It never occurred to me that our Castlecaulfield Horticultural Society group would be invited.