I moved to Myanmar to work in the country's young advertising industry. However one strange afternoon I found myself in a film studio, perched on a wooden stool, with a film crew of 20 people staring intently at me.

I had been cast as the talent in an ad for a local whiskey. The whiskey wanted a Scottish-looking face, which are in short supply in Myanmar, and I fit the bill.

I soon discovered Myanmar whiskey ads don't use apple juice. They also involve a huge number of takes. I had to sip with greater satisfaction, swill with more meaning and look more confidently into the camera at the end. A production assistant kept running on stage to top up my glass.

This was all part of the unpredictable world of advertising in Myanmar – a long-isolated nation that has suddenly become the next frontier for Western brands.

In 2012, Myanmar, also known as Burma, was transformed almost overnight. The country had been off limits to western brands due to sanctions. Along with North Korea and Cuba, it was one of only three countries in the world where Coca-Cola did not do business. Then Myanmar's new government unexpectedly started democratizing the country. The west lifted sanctions, and the floodgates opened to a market of 60 million people.

There's now a gold rush as foreign brands compete to be the first movers in this uncharted market. Local brands are fighting hard to beat off the competition.

I went to Myanmar to set up the country's first planning department at Mango Marketing, the leading advertising agency in the Southeast Asian country. Mango had recently become an affiliate of JWT. It was an exciting time to be there. Our meeting room was always full with international companies looking to enter the market.

My planning team went from me sitting by myself, to a department of five people. Almost every week we had new work. One day we would be talking to the master tea maker in a traditional tea shop about his milk choices, the next we would be promoting an isotonic drink with the Myanmar national judo team.

Many brands re-entering Myanmar are finding that their image is stuck in a time warp. The last time anyone heard from them was in the 1960s.

Some discover that a Myanmar version has sprung up in their absence. A run-down chain of convenience stores selling suspicious medicines looks identical to 7-Eleven. A man pulls a KFC cart through downtown Yangon shouting for people to buy his chicken; needless to say he isn't Colonel Sanders. Burger Queen and Macburger fight it out in the fast food market.

The Myanmar people are watching a country that was always sealed off to the world suddenly open up. The big question for brands is what role they can play in making sense of this change.

I spent days travelling around tiny Myanmar villages, doing research for the first foreign cell phone company entering the country. A couple of years ago, SIM cards were so rare they cost $2,000. Now they cost $150. Next year they will cost $1.50.

It was our job to understand what it meant for a consumer to watch the cost of a SIM card fall from $2,000 to $1.50.

People in Myanmar are very friendly, and as we approached, farmers would lay down their tools and invite us into their homes. Nobody seemed to question why a British man had pitched up to ask them about their mobile phone usage.

I remember one old farmer with a huge toothless grin talking about what a mobile phone would mean to him. His only son worked in China, and once a month he had enough money to afford a phone call. So he would cycle 6 miles to the nearest town where there was a phone he could use. The line normally cut out. A mobile phone would mean bringing him closer to the person he cared about most.

This sense of hope and optimism echoes across Myanmar. Foreign brands, from fast cars to beers, are searching for their way to tap into this. When a country suddenly moves from dictatorship to democracy, the appearance of Western products on the shelves of the village store is one of the most tangible symbols of change.

Back at the whiskey film studio, however, the director didn't have the same hope and optimism in me. After hundreds of takes, he decided this was the best he was going to get, and finally called cut. I left the studio ready for my new life as a Myanmar celebrity, but for now struggling to walk straight.