To Hartson's eternal credit, he has never kept on the right side of people by spouting what they would want to hear. Yesterday was no different. Having dealt with the formalities of explaining his frontman status in SuperStar Call, he was gently lobbed an easy-way-in-to-Celtic poser. It was typically Hartson that he whacked in a completely unexpected direction.
For a ringing endorsement wasn't notably forthcoming when given the opportunity to big up the role former Celtic team-mate Johan Mjallby could play in earning another of their kind, Neil Lennon, the Celtic manager's job. It is a position he so desperately wants for the midfielder who was by his side for trophies and triumphs never-to-be forgotten throughout his six years at the club from 2001.
Mjallby he overlapped with until the Swede headed to Spain in 2004. And he didn't see enough from the titanium-tough defender in that time to be other than "surprised" Lennon has parachuted Mjallby in as his right-hand man for his stint as interim manager; effectively a trial period to see if he could be permanent successor to Tony Mowbray, last week removed from the post after only nine months. Moreover, Hartson painted a very different impression of the Swede from the roaring warrior-type he is always sketched as.
"I didn't really know that Neil was that tight with Johan," Hartson said with typical frankness. "I didn't see it. I'm sure he can help defenders.
"He was a great defender himself, though that doesn't always mean to say he'll be a great coach. I'm the wrong person to ask about what he can bring. I know Johan's attributes as a player, as a leader. He was a great defender. He was not particularly someone who spoke that much in the dressing room. You could go and have a drink with him, he was great company but I don't really know."
Hartson knocked out the park any suggestion that Mjallby, Lennon or anyone could rid footballers of a mental softness – a vice the interim manager said he would have to eradicate from the squad he inherited. The Welshman said it will be points and a prize that will determine whether Lennon is getting the right to remain in the job.
"Managers can say the right things, and can go and tell you to put your head through the ball. But you didn't have to go and tell Richard Gough to head the ball. He'll go and head it. It didn't take Walter Smith to tell him that.
"Martin O'Neill couldn't tell Bobo Balde to go and be brave, he was naturally brave.
"Johan will work with the defenders, get organisation there but it is all about whether Neil goes and wins the Old Firm game or the Scottish Cup. He'll never get a better chance with the game against Ross County in the semi-final and Rangers not even in the competition. If he picks up the Scottish Cup it is a great trophy to have in the locker.
"I played in two finals, won one, lost one, and they were great days out for the supporters. It is a great opportunity. If he can win the last Old Firm game, reduce the deficit in the league, to five, six points or whatever, then the club do not have to be looking for a manager right now. Neil will be given the opportunity."
He added: "I think it's Neil's job to lose now. It didn't work out for Tony although I thought it was a match made in heaven, I thought he was perfect for the job.
"But if a manager comes in and settles things down and starts winning big football matches and trophies then it is his to lose. Players can only get experience by playing and it's the same with a manager. How is Neil going to get experience if he is not given a chance?"
Hartson has required six operations, two on the lung and two on the brain, to enjoy his life as he is right now after being diagnosed with testicular cancer that spread to his brain last summer.
He is "really busy" with a newspaper column, television punditry work and looking after his four-week-old daughter Stephanie, the second child with his current wife Sarah, and fourth in his brood, having two older children from his previous marriage.
That ended in a divorce which he confessed "cost him a lot". He is happy simply to have a full life and be involved in a new business that isn't "a pub, or something like that". Although he has all his coaching badges, he doesn't feel ready to return to the game.
"I've put it on the backburner, I'm so busy and looking to make a full recovery and get all my strength back.
"I've still got some blood test and scans to come, but I've made great progress and just not looking at coaching or management just now."
Hartson's comments on it are worth so much more than many who make it their profession full-time, as he surely will again one day.