At the event they played at the guests were all smartly attired and it was all quite formal.
But as The Corrs launched into a rollicking Irish song they watched in wonder and delight as one person got to his feet and began to dance - grinning and bopping.
It was Nelson Mandela.
"He was doing what had become known as the Madiba jive,'' Sharon said.
"It was an incredible moment and it symbolised him - he was never afraid to do something that maybe the rest of the people around him in the room would not do.''
She also spent days with him during a charity work visit to a safari park in South Africa.
"I would sit and just chat with him - it was lovely.''
Sharon said growing up in Ireland during the 1970s and `80s made her well aware of the world and its "realities''.
"We seem to lurch from one crisis to another.''
So she became involved in a succession of campaigns and causes, including support for the families and victims of the Omagh bombing. The band members were all awarded MBEs in recognition for their work.
She is now the face of Oxfam Ireland - Oxfam works globally to end poverty and injustice.
She spent 15 years with The Corrs as the band took their blend of Celtic pop/rock to the world - which responded in the form of about 45 million album sales and a string of hits like Runaway, So Young and Breathless.
There were no regrets at calling it quits.
"We achieved great success - it was crazy at times - but it is very important for us to have our own lives and families. It's a `no regrets' scenario.''
Growing up, the children were surrounded by music.
Her mother sang and her father played keyboards and they had a band going - ``it was how they escaped''.
They set the groundwork with Sharon choosing to play violin which she began to learn when she was just six.
"It is very hard to learn but it is unique - it is my second voice,'' she said.
The audience at the Mission Concert will hear her extraordinary ``second voice'' and she is relishing the opportunity to again play with an orchestra.
"I started playing classical violin and I've worked with orchestras so it's a natural environment for me - I love the depth it brings.''
She is still sorting her full Mission song list but at this stage she's pretty well settled on doing So Young and Radio, as well as Smalltown Boy as well as chip in a fine and fast traditional Irish reel.
"I love to perform and love to sing to an audience - to be fully in the music and pull the crowd toward you,'' she said, adding she was looking forward to seeing a part of New Zealand she had heard a lot about but never made it to before.
"I've heard it is beautiful and I hope to spend some time there. I've looked at the Mission website and it looks like a great place, I can't wait.''
She has met her co-Mission artist Melanie C ("she's a sweet girl'') and has appeared on the same bill and dueted with Ronan Keating.
Will we see a duet at the Mission?
"You never know.''
She is passionate about music and loves the abilities of a voice, and is critical of over-produced music which clouds a voice.
At the moment she is fizzing about a trio she heard while in Germany on holiday recently.
The Mighty Oaks - three guys from three countries and based in Berlin who she said launched into music with voice and strings which she described as "crazy''.
"It is just them. It is great - nothing is covered up by over production.''
In 2001 she married Belfast barrister Robert Bonnar and they have two children. And yes, the youngsters, a six-year-old girl and a seven-year-old boy, very much have music in their lives.
"They have been exposed to music from the very start and they are musical. But I did not put them into lessons too early - music has to be a love.''
They have started piano lessons, so what was the chance that one day the kids might play in a band with their mum?
"Oh no, I wouldn't do that to them,'' she laughed.
The 2014 Mission Concert is on Saturday, February 15
