Ireland will perform third last tonight

Irish Eurovision fans are gearing up for tonight's grand final, which will see Ryan O'Shaughnessy compete against 25 other countries.

He'll perform third last with his song 'Together' in Lisbon's Altice Arena.

Organisers say the running order was decided to ensure "each act has the opportunity to stand out".

"The producers look at the genre of music, whether a song is performed by a solo singer or group, the use of props, music tempo and various other aspects of each act," they say.

The show will be opened in traditional Portuguese style by musical performances, followed by a flag parade.

Twenty-six acts take part with the so-called 'Big Five' - France, Germany, Italy, Spain and the United Kingdom - and host country Portugal already pre-qualified.

Last Tuesday, Ireland and another nine countries qualified in the first semi-final.

On Thursday, another 10 countries won their ticket for the grand final.

Fans pose with Ireland's Ryan O'Shaughnessy and a Tricolour flag in Lisbon | Image: Supplied

During the show, people are being encouraged to use the #Eurovision and #AllAboard hashtags on social media.

After all songs have been performed, people can vote for around 40 minutes.

Televotes make up 50% of the result - the other 50% was decided by a professional jury.

The contest is being shown on RTÉ 1 and BBC One from 8.00pm.