The Countess of Verulam will be a guest of honour at the event, which is being held at the Aldwickbury Park Golf Club in Harpenden on Saturday, April 1.
The branch’s President, Denise Powell, said: “It is going to be a really exciting affair.
“We have the daughter of one of our members performing so it is going to be really nice celebration.”
The Countess and the other guest of honour, former Soroptimist International president Ann Garvie, will be joined by 140 guests.
The guests include members of the local branch, as well as members from partner branches in the USA, Japan, and Poland.
Denise said: “Each Soroptimist club has friendship links with clubs in other countries and this the first time ever we will have representatives from each of our four friendship links.”
The branch has also been running a ‘60 for 60’ programme, with the intention of completing more than 60 projects this year.
These projects have included an International Women’s Day radio broadcast, a quiz night to raise money for domestic violence charity Women’s Refuge, and carol singing at Harpenden station.
Denise said: “We’ve had an amazing success.