Harper is relishing the prospect of a return to European action at the age of 37.
He said: "It's fantastic to be back in Europe. All credit to the gaffer and the players last year, they were outstanding and earned the right to be back here.
"It's great for me - I remember when we went out of Europe the last time, and a lot has happened in the not too many years between then and now.
"But I know a lot of people, and I am sure the fans, will say that we are back where we belong, and hopefully we can stay in this competition as long as possible."