McGeechan featured on two tours as a player, starting eight Tests in a row and starring in the historic 1974 series win over the Springboks, before being involved on a further five occasions as a coach.
And having led the Lions on their latest adventure to South Africa, McGeechan has now returned to the club game after accepting a role with Guinness Premiership outfit Gloucester Rugby.
McGeechan has agreed to join the Cherry and Whites in an advisory capacity with immediate effect.
"It's a terrific challenge. Gloucester as a club really do have so much potential," said McGeechan, who has previously worked for English Premiership sides Northampton Saints and London Wasps.
"I think, as is shown by recent results, that things are certainly moving in the right direction under Bryan Redpath and the rest of the coaching staff.
"It's a great club, a real rugby club with a great stadium and tremendously loyal supporters. My job now is to work with Bryan with the aim of helping Gloucester take the next step and realise their massive potential.
"I'm very excited to be involved. I've already been around the training ground and met everyone and can't wait to get started."
Gloucester currently sit in ninth place in their domestic league but four wins in their last four games has seen them reach the quarter-finals of the Amlin Challenge Cup and the semi-finals of the new LV = Cup.
Unsurprisingly, director of rugby Bryan Redpath is delighted to be able to work with one of the game's most respected figures.
"I've known Geech for many years now and his record speaks for itself," said Redpath.
"In this game, you can't afford to stand still - you need to keep looking for ways to improve things.
"He is unique in the game of rugby union and the opportunity to work with him and benefit from his knowledge and experience is fantastic."