Collins showed not a flicker of emotion when Craig Brown sprung the news on him at a press briefing. But inside, the 28-year-old midfielder was "glowing". He went back to his hotel room and phoned his parents.
For the unflappable Collins, whom the Scotland manager has deputed to "lead by example" in the World Cup qualifier against Estonia, the appointment is the culmination of the headiest five months of his career. It began when he became the first British player to move abroad in the aftermath of the Bosman case, joining Monaco from Celtic.
He then showed English clubs what had been under their noses by brimming with industry and invention during Euro 96. Now, with Monaco second in the French league, the boy from the rugby heartland of the Borders will achieve "the ultimate honour" by standing in for the suspended Gary McAllister.
Collins, who set up Scotland's 2-0 win in Latvia on Saturday with a typically clever goal from a free-kick, has worked long and hard to be an overnight success. Though his international colleagues rib him about his reputed salary of pounds 1m a year, tax-free, they are pleased for a player who started out on the Hibernian groundstaff at pounds 30 a week. Some pounds 16 of that went on the bus fares from Galashiels to Edinburgh, a trek which started at 6.30 each morning.
In his early teenaged days Collins' burning desire had been to play for Celtic, who overlooked him in their Boys' Club side and ended up having to buy him for pounds 920,000. He gave them six years' service, but on approaching the end of his contract last season he was increasingly tempted to test his ability in a Continental context.
"Celtic had inquiries from Chelsea, Coventry, Middlesbrough, Everton and QPR," he said, "and I thought I was certain to go to the Premiership. But when I became a free agent a number of overseas clubs were also interested. I was going to cost an English team pounds 3m whereas Monaco could get me for nothing."
Collins had no doubts about the technical excellence of the French game. He remembered the awesome quality of the Paris St-Germain team who brushed aside Celtic. He noted, too, how Bordeaux knocked out Milan, and that Nantes lost narrowly to Juventus in the Champions' League semi-final.
First, though, he had a question for Monaco's coach, Jean Tigana, who in his prime alongside Michel Platini was similarly compact and creative: "I asked him what kind of player he saw me as, and was relieved that he'd realised I wasn't a winger or a wing-back. He uses me on the left of three in central midfield, with Enzo Scifo on the right and a 'sitter' between us."
Needing to master his new language in a hurry, Collins was fortunate that a French professor in Glasgow offered to make him conversational in a fortnight.
"He spent every day with me in Monte Carlo, for 12 hours solid," he recalled. "It was hard work but I did my first interview in French after 12 days."
The dressing-room patter was only one of several differences he discovered. "French football is like another sport altogether from the Scottish game, which tends to be 100mph, 'go-go-go' stuff. At Monaco, it's as if we're playing a European tie every week. It's slow, slow, pass it around at the back and through midfield, and then there's a sudden explosion of pace.
"When the opposition get the ball, they do the same, so you're getting more of a rest. Initially I was rushing to close players down like I would in Britain. I noticed my team-mates weren't going along with me, so I've had to adjust to their style."
Before kicking a ball in earnest, he had to subject himself to Monaco's scientific training regime. Club doctors analysed his blood to see whether he lacked sugar or iron or vitamins. Then they wired him up and had him pounding a treadmill, like a rodent in a laboratory experiment, until he could run no more.
A computer revealed which muscles weakened fastest, and Collins was assigned exercises accordingly. "Training now is mainly sprint work designed to give you that explosiveness," he said. "But at the pre-season camp they had us running in the forest at 7am and coming back for more throughout the day. I was so tired afterwards I just went back to bed. Now I feel stronger and sharper."
The level of technique was even higher than he anticipated, with everyone so comfortable on the ball that Collins could not tell who the defenders were when they played five-a-sides. In the afternoon, when many British contemporaries are on the golf course, Monaco's players hone their skills.
"I'm there to work, but it's great for my family. The sun's shining. The environment's clean and healthy. And we live by the beach, so we can go and relax after training, which is something we could never do in Glasgow."
Nevertheless, Collins confesses to missing certain aspects of the Scottish scene. The changing-room clamour at half-time, to give one example, which contrasts starkly with the near silence in France.
The crowds for another, or more specifically Celtic's cacophonous following. Monaco attract around 5,000, one-tenth of his old club's most recent gate. "I knew I'd never find another atmosphere like Parkhead, which is the best in Britain if not the whole of Europe."
Yet the passion pouring down from the stands can, in Collins' view, be counter-productive. "Tommy Burns is trying to play a passing game at Celtic, but it has to be passing at tempo. The punters would never tolerate the patient way we build from the back at Monaco.
"To be successful in Europe, British teams have to learn to keep the ball. They burn up so much energy charging around trying to win it back. Celtic and Rangers fans love to see commitment, but too often it's channelled in the wrong way."
That presumably accounts for the perception of Scottish football held by Tigana and his team - "not very good at all", Collins conceded - which in turn strengthens the temporary captain's resolve to help Scotland reach the finals being staged in the country that will be his home for the next three years.Reuse content