Former Rangers and Scotland manager Walter Smith is recovering in hospital after undergoing an operation on Monday, the club have confirmed.
Smith, 73, won 21 trophies with the Ibrox club in two separate spells as manager.
He also spent three seasons in charge of Everton from 1998-2002 and was manager of the Scottish National team for three years between 2004 and 2007.
In a statement, the Scottish club said: 'Rangers Football Club can confirm Walter Smith had an operation on Monday and he is currently recovering in hospital.
'His family have requested privacy at this time.'
Smith first took charge of Rangers in 1991, taking the reigns from Graeme Souness who had left the role to join Liverpool.
In his first spell at Ibrox, Smith won seven Scottish Premier League titles in a row as well as three Scottish Cups and three Scottish League Cups.
After losing the 1997-1998 SPL title to Celtic on the final day before a Scottish Cup final defeat by Hearts, Smith briefly retired from management. However, that only lasted a month before he was appointed by Everton.
Smith endured a difficult spell at Goodison Park and was sacked in 2002 with fellow Scot David Moyes replacing him.
He briefly served as assistant to Sir Alex Ferguson at Manchester United in 2004 before he was appointed manager of Scotland at the end of the year.
Despite failing to qualify for a major tournament, Scotland made significant progress under Smith - moving up 70 places in the FIFA rankings and securing a famous Euro qualifier victory over France in 2006.
Smith returned to Rangers in 2007 after Paul Le Guen was sacked following a poor run of results. During his second spell at Ibrox, Smith led the club to their first European final in 36 years, where they were beaten by Zenit St Petersberg.
He also managed another three SPL titles, two Scottish Cups and three League Cups.