Eurovision 2015 officially got under way with the first semi-final live from Vienna, combining the usual winning mix of crazy costumes and eccentric acts.

Viewers were as ever bemused by some performances and bowled over by others – but which provoked the strongest reactions on Twitter?

Moldova

Opening the contest was an enthusiastic Moldovan act, Eduard Romanyuta, with singer and backing dancers kitted out in skimpy latex police outfits.

Belgium

Belgian entrant Loïc Nottet went for it with his big voice ballad, but some viewers seemed more taken by his looks than his singing.

Finland

Eurovision fans felt that the Finnish act, Pertti Kurikan Nimipäivät, who all have learning difficulties, summed up the spirit of the competition.

Serbia

Bojana Stamenov looks to be onto a winner with Beauty Never Lies, penned by the writer of last year’s winning Rise Like A Phoenix which was of course performed by Conchita. Can the songwriter have struck gold for a second year running?

Denmark

The Danish group, Anti Social Media, were one of the smiliest boybands ever to have graced the stage, but they split opinion among viewers.