Graham Norton has revealed he was overwhelmed by the fandom surrounding the Eurovision Song Contest.

The 52-year-old chat show host, who will be giving the British commentary at the grand final tonight (May 23), admitted he underestimated the passion for the competition when he took over from Sir Terry Wogan in 2009.

“Before I started commentating, what I didn’t understand was the scale of the thing,” he said.

“The first year I did it was in Moscow, and that is a big city. Eurovision literally took it over! There were Eurovision lanes for buses and cars, there were flags everywhere – Eurovision was all anyone was talking about. The press area alone is the size of a small town.”

Graham continued: “People think that it is just a big concert that is on for one night only but it is so much more than that. There are semi-finals, parties, embassies getting involved, there is so much going on.

“I think that for people just watching at home that is the thing that you don’t really get, just how vast this thing has become.”

The presenter admitted he is slightly baffled why Australia – represented by Guy Sebastian – is taking part in the competition, as part of its 60th anniversary celebrations.

“For Australia this is a great way of marking the 60th anniversary but I am not entirely sure what anybody else will get out of it,” he said.

“I have nothing against Australia but no-one has convincingly explained to me why they are in it!”

Irish-born Graham said the Swedish entry – Mans Zelmerlow’s Heroes – is a highlight for him.

He said: “The bookies’ favourite is Sweden and that is a really big upbeat catchy song and they are always really popular at Eurovision. Oddly, I rather like Austria’s entry by The Makemakes called I Am Yours.

“There are so many big produced ballads this year and I thought Austria’s was a very simple, sweet ballad.”

The Eurovision Song Contest final will air on BBC One at 8pm.