Pat Rice, Arsène Wenger's former assistant manager at Arsenal, has been admitted to hospital with cancer.
Rice first joined the Gunners as an apprentice in 1964 and was part of the club's double-winning side in 1971, before he captained the club to FA Cup glory in 1979 against Manchester United.
Rice returned to Highbury as youth team coach, winning two FA Youth Cups in 1988 and 1994, before he took up a senior coaching role when Arsène Wenger arrived in 1996.
The 63-year-old helped Wenger guide the club to three Premier League titles and four FA Cups, including two domestic doubles in 1998 and 2002.
"Our thoughts are with Pat and his family. Everyone at Arsenal sends him our best wishes," an Arsenal spokesman told the Daily Mail.
He made 528 appearances for Arsenal across 14 seasons and ended a 44-year association with the club when he stepped down as assistant in 2012.
Rice was awarded an MBE for his services to sport in the 2013 New Year's Honours List.
All at Chelsea wish former Arsenal assistant Pat Rice a very speedy recovery from cancer. One of football's finest. #GetWellSoonPat— Chelsea FC (@chelseafc) November 28, 2013