"From watching Braveheart," he says, grinning.
"Isn't that the way most Scots learn about their background?
"And what I didn't learn from watching movies such as Rob Roy and Brigadoon, I picked up from going down to Wembley with the Tartan Army."
What's clear is that Des, who grew up in Glasgow's East End, didn't gain a comprehensive history education at his local comprehensive, St Gregory's.
His mind at the time wasn't focused on academia.
But now, Des has been studying up on what it means to be Scottish. And he's set to share his discoveries with the rest of the nation, in a new touring comedy show, Des McLean's A-Z of Scotland.
The comedian and impressionist - he's famous for his take-offs of the likes of Billy Connolly and Tommy Sheridan - will appear at theatres up and down the country.
And TV development talks are currently taking place with a view to Des fronting his own sketch show, based on his A-Z idea.
He smiles as he explains how he delved into the past for ideas.
"Some of my regular fans were asking what I was planning for this year and I reckoned because it's the year of the independence referendum, the Commonwealth Games and the Homecoming, I'd have a look at what Scotland really is all about.
"And in the process I've educated myself. And I've discovered some comedy gold.
"For example, Scots may not know that the kilt was actually first created in England, haggis was invented in Greece and bagpipes came from ancient Egypt.
"But the chicken tikka masala was invented in a curry house in Gibson Street in Glasgow in 1969."
Des adds, grinning; "The amount I didn't know about Scotland was immense. I realised English people knew far more about Scotland than I did. "
Des's show will feature filmed vox pops with local people talking about what defines Scottishnesss.
And during his A-Z show he will offer up some of his classic impersonations and Radio Clyde voices.
"You can be sure Connolly will be in there. And Tommy Sheridan of course, given I spent most of last year appearing as Tommy in the stage show.
"But I've also been studying Alex Salmond a lot on YouTube and I think I've got his voice now as well. And I'm going to have fun with it."
The show will feature some classic themes.
"The Scots have a great capacity to be able to laugh at themselves. And we can be a bit excessive. That's why letter 'A' in the A-Z will stand for Alcohol.
"I'll be looking at reasons why Scots, when going on holiday, have to have a pint of lager at the airport bar at four in the morning. Just because you've got the thought of palm trees in your head doesn't mean your liver's no' going to get tanned just the same.
"And there's our developing love affair with wine. But we don't select it on its grape quality, regional history or its tanning. No, we look at the label and see '14.5 proof - that'll get me tanned'."
There are other aspects of our national character Des plans to shine the spotlight on.
"We complained, rightly, about being lab rats for the poll tax. But when we kicked off the No Smoking ban we complained about that as well, in spite of the fact it was about saving our lives.
"And I think the letter 'H' will be about holidays. For example, why is it when you go on holiday and another Scot hears your accent they want to hijack you for the week?"
The letter 'B' could well stand for Bravery, Des informs, laughing.
"We're a really tough nation. Look at the battles we've fought over the years, and how John Smeaton tackled the bombers at the airport.
"But why is it we're really brave until one of us goes on the X Factor and ends up greetin' like a big wean?
"I'll also be including a feature about weather," says Des. "It will ask why Scots don't like it. We can't cope with heatwaves or bad weather. We just love to moan."
The show will also feature a range of surprise guest actors, singers and comedians.
And the DVD of the show is already being planned, with the new show be launched, and filmed, in his own East End backyard, at the Platform in Easterhouse.
"It's a bit like Rocky defending his title in his home town of Philadephia," he says, grinning.
"I can't wait."
l Des Mclean's A-Z of Scotland, April 11-12 at the Platform and runs for three months at theatres throughout Scotland