Model Christie Brinkley paid tribute to her ex-husband Billy Joel's late mother by writing a heartfelt letter praising the family matriarch.

The Piano Man's mum, Rosalind Nyman Joel, died aged 92 on Sunday (13Jul14) at a hospice in Long Island, New York.

Brinkley and Joel's marriage ended 20 years ago, but the blonde beauty was moved to write an post about her former mother-in-law, who was grandmother to the former couple's daughter Alexa Ray Joel.

Along with a youthful black and white photo of Rosalind, Brinkley added in the caption, "At sad times we look for ways to find the good to lift our spirits, So I have only to imagine what Rosalinda's Eyes have seen to find cause to celebrate a life well lived!

"Just in this year alone she saw her son, (Billy Joel) receive the Kennedy Center Honor, the highest cultural honor possible, from the President of the United States no less, and Rosalind greatly appreciated the arts (sic)!

"She also saw her son get a regular gig at Madison Square Garden (where he already holds a record and where Roz is welcomed on a first name basis!). And her eyes sparkled with pride and joy as the former Gilbert and Sullivan chorus girl, watched her granddaughter Alexa perform at the famed Cafe Carlyle surrounded by a large group of her friends enjoying themselves.

"I know as a mom myself that when you see your kids happy healthy and enjoying their passions you feel content and happy. Rosalinda's Eyes will live on not only in the song inspired by her, but in Billy, and Alexa... and Nanny Roz herself would find that worth celebrating. #cherishedgrandmother #restinpeace (sic)."