Heaton was selected by manager Roy Hodgson for the friendly against the Republic of Ireland and European Qualifier in Slovenia next month.
Heaton said: "It's difficult to put into words. When the manager told me it was almost difficult to believe and then there was a euphoric flood of emotion.
"It's been a dream of mine since I was a little kid and pretty much everything since I started playing has been geared towards trying to get there.
"This isn't the final step because the dream goes beyond this, but it's certainly a great step along the way and I'm absolutely thrilled."
The 29-year old put in impressive performances for the Clarets throughout the Premier League season but failed to save the Lancashire club from relegation.