Former MLA Jo-Anne Dobson is currently in surgery donating a kidney to her son.
Mark, who had kidney problems from birth, received his first kidney transplant in 2009 but lost his donated organ in August last year.
This morning Mark Dobson wrote on his Twitter account @DialysisDobson: "LOVE you Mum, you are making my dreams come true this morning! XX "Mum’s just gone down to surgery to donate a kidney to me - I’m heading down around lunchtime! Thanks for all the lovely messages of support. #KidneyTransplant 💪".
On Monday night Mrs Dobson wrote on Twitter: "In the morning Mark & I place our lives in the hands of a hero! An emotional night for us at Belfast City Hospital until a new day dawns & Mark receives new life from me for a 2nd time as I donate a kidney to him."
"In the morning we place our lives in the hands of a hero!
"Mark & I are preparing for our Kidney Transplant at the City Hospital looking over Belfast from the 11th Floor of HOPE!
"We’re both nervous & excited but know we couldn’t be in better hands than our Consultant Transplant Surgeon Tim Brown & can’t speak highly enough of the care & attention we’re receiving.
"It’s just like Christmas Eve here as tomorrow Mark’s preparing to once again receive the ultimate gift – the gift of life!
"Thanks for all your support & prayers – they mean the world to us!!"
She recently became the Northern Ireland charity ambassador for the patient support charity Kidney Care UK.