Graeme Souness believes Walter Smith's decision to join the Rangers board brings enormous credibility to the Charles Green regime at Ibrox.

The club announced on Sunday evening that former manager Smith and retired Glasgow businessman Ian Hart had accepted the role of non-executive directors.

The moves come five months after Smith tried to lead a bid to buy out Green's consortium, who purchased the business and assets of Rangers for £5.5million after they were consigned to liquidation in the summer.

Green rebuffed those attempts and instead tried to persuade Smith to join his group and, having now succeeded in bringing the veteran boss on board, Souness - who managed Rangers between 1986 and 1991 - feels Green has pulled off a major coup.

He said: "It's a good move. Walter is Mr Rangers in modern history and it can only be good for the club.

"I'm sure Walter has not taken that post on without doing some due diligence. He's looked into what's going on at the club and what's behind the club and he obviously feels it's right for him.

"Walter is very much his own man and the credibility that brings to Rangers now is enormous. No-one knew Charles Green coming in to Rangers. So far, so good.

"But, in my opinion, if I was a Rangers supporter, I would be very, very happy that Walter is involved again.

"Forget him just being involved and the knowledge he brings, it validates more of what Mr Green is trying to do."

Fans were initially reluctant to trust Green in the wake of the disastrous Craig Whyte stewardship, but have gradually been won over.

And Green believes Smith - who managed Rangers to 10 league titles in two spells - can play a major role in the Light Blues' ongoing recovery.

He told talkSPORT: "We have spent a lot of time together, this is not a spur of the moment decision from Walter. People who know him know he is a very, very deep thinker.

"He is passionate about Rangers and it's a big decision for him, he is not making this decision lightly.

"Walter knows we aren't going to let Rangers down and he's fully supportive of what we're doing.

"Walter is delighted to be back at the club and I'm sure all the fans and the board concur with my thoughts that we couldn't get anyone better to bring onto the board.

"Walter's got a great amount of knowledge of not just Scottish football but world football, and part of where we are trying to get the club is back into world football, where Rangers belong.

"I think he will be pivotal in helping us do that."

Green also hopes Smith's involvement can help ensure the success of a £20million share issue.

He added: "It's going very well. The fans have been fantastic. We've got commitments from the supporters and, I have to say, prior to this announcement, they were at over £20million.

"So one would expect that this endorsement from Walter of what we're doing would also encourage people."