Sonny Bill Williams has posted a heartfelt tribute to his grandmother who died last night.

Williams confirmed the sad news on Twitter, posting an image of him holding his grandmother's hand tightly.

He wrote last night that he lost one of his most loved, his nana.

Yesterday saw families across New Zealand celebrate Mothers Day, and Williams had tweeted since that we should cherish every day we have with our mothers and grandmothers.

Meanwhile, in the Super Rugby the Crusaders play the Highlanders at 7.35pm Friday.