The Michelin-starred chef was among the friends at this week's Daniel O'Donnell concert at a community centre in Newcastle, Co Dublin, which raised €100,000 for the charity As Darragh Did.
Andrew McGinley set up the charity a year ago in memory of his three children, Conor, Darragh and Carla, who were killed by their mother - his wife Deirdre Morley - in 2020.
She was later found not guilty of their murder by reason of insanity.
Recalling their personal friendship this week, Derry Clarke told the
Sunday World: "Andrew worked with me in Patrick Guilbaud's all those years ago before he joined the food services company Sodexo.
"I'm lucky enough to be a consultant chef with them for the last 15 years, so we've worked together over the years at different events and he's a great guy.
"Obviously, the tragedy that came to him two years ago was just devastating, and for me especially on a personal level having lost a child to suicide."
Derry's son, Andrew, who at 16 died by suicide 10 years ago. "I just knew that loss and emptiness that Andrew (McGinley) would have felt, so we have something in common that we don't want to have in common."
He said the pair often meet up for walks and chats. "I live not too far from Andrew in the Dublin mountains," Derry says. "We go for a walk around the woods there and have a chat and a reflection on what life is.
"It's very difficult to move on from something like that. It must be really, really hard for him with his whole family gone. I don't know how you come out of it really.
"There are no words sometimes to describe things and I think that is the one instance where it's really difficult to face up to it and talk about it really."
Derry said that family and friends helped him and his wife, Sallyanne, to cope with their bereavement.
"We had good close family and friends and initially we talked about it and went through the whole thing.
"For us it's 10 years ago now and you have to move on in life because the trouble is that life does move on and you can't keep going back to that time. If you keep going back to that time there is nothing left."
Speaking at Thursday night's concert, Derry added: "To have the great Daniel O'Donnell come and perform here in the local hall for 250 people is great.
"I think it's part of the healing process for Andrew. I'm sure tonight will help him to move on further and maybe have a better future for himself."
Daniel said he felt "privileged" to support As Darragh Did, which supports clubs and events for children all over Ireland.
He said: "I met Andrew for the first time (on the day of the concert). My impression is that he is broken and yet he is very strong.
"I can't even imagine how he manages every day, but somehow he does. He is obviously inspirational because you have to be inspirational to be able to do what he is doing."
Andrew told how Daniel O'Donnell has given his charity a major boost by raising a phenomenal €100,000.
"The As Darragh Did charity is barely a year old and to have Daniel O'Donnell, the biggest act in Ireland, to step forward and do this for us in our local hall here in Newcastle was just amazing," he said.
"As soon as he walked in the door I just burst into tears. I can't thank Daniel enough. He has given us a great start to what I hope is a charity that lasts many years helping many projects across the country."
You can make a donation to the charity through the website www.AsDarraghDid.ie.