In Tuesday's semi-final, Portuguese singer Salvador Sobral drew some of the loudest applause with his song 'For The Both Of Us' - a lilting, jazz-style ballad written by his sister.

The pitch-perfect performance was not typical fare for Eurovision, an annual contest watched by millions across Europe that is better known for its flamboyant costumes than its polished vocal acts.

Among the recent qualifiers, Sobral, Armenian songstress Artsvik and Sweden's Robin Bengtsson are in the top five favorites to win Saturday's final.

Italian singer Francesco Gabbani, whose back-up dancer is a man in a gorilla costume and bow-tie, is seen as the frontrunner.

Tuesday's other qualifiers for the final were Moldova, Azerbaijan, Greece, Poland, Australia, Cyprus and Belgium.

Eight countries missed out on a final place, including Montenegro's Slavko Kalezic, whose hair-twirling performance in a see-through shirt and long, silky skirt recalled the 2014 champion, bearded drag queen Conchita Wurst.

The competition has a political edge this year due to the absence of Russia, whose entrant Kiev barred from entering Ukraine because she had performed in Crimea after its annexation by Russia.

Ukraine won the right to host the contest after its 2016 entry came first with a song about Stalin's mass deportation of ethnic Tatars from Crimea during World War Two.

The full list of finalists will be announced on Thursday, after the second semi-final.