Pat Lampard, mother of Chelsea midfielder Frank and wife of former West Ham United player Frank Senior died on Thursday, Chelsea said in a statement.
The 58-year-old had been in hospital for 10 days suffering from pneumonia and Frank Lampard had missed two league games to be by her bedside.
After an improvement in her condition he returned to action in Tuesday's Champions League semi-final against Liverpool and had been expected to play in the virtual title-decider against Manchester United on Saturday and next Wednesday's semi-final second leg.
"Everybody at Chelsea is absolutely devastated to hear the tragic news of the passing away of Pat Lampard," the club said on www.chelseafc.com.
"Pat was a very familiar face to many people at Chelsea. Her unswerving support for her son's career was evident at virtually every game that Frank participated in regardless of where it was being played, she would always be there to watch him with Frank's dad. Pat will be deeply missed by everyone at Chelsea."
