The Ahern ladies showed their style credentials when they attended a summer lunch for charity which was hosted by Miriam.
The three women cut a fashionable dash at the annual summer lunch, in aid of CARI, which was held in Malahide.
Best-selling author Cecelia Ahern showed off her enviable post-pregnancy figure, wearing a glamorous black dress.
It was one of her first public appearances since giving birth to her daughter.
Cecelia (28) is currently taking a break from her literary career this year to concentrate on her new role as a mum to five-month-old baby Robin.
But she is still making waves in the book world -- as she is one of the front-runners to win the title of Irish Book of the Decade with her debut novel PS, I Love You.
Her sister, Georgina Byrne, who is married to Westlife's Nicky and mum to Jay and Rocco, opted for a stunning one-shouldered grey silk dress for the occasion.
Meanwhile Miriam, who attended the event with her partner Terry McCoy, wore an on-trend blue and white flower printed dress.
Live entertainment at the event was provided by top singer and performer Paul Byrom, and TV3's Alan Hughes was the MC for the afternoon.
The CARI annual lunch raises in excess of €20,000. Other familiar faces at the event yesterday were Yvonne Keating and model Alison Canavan.
CARI relies on this fundraiser to help provide therapy for children. Money raised from the lunch is essential to CARI maintaining its level of service.