Where is it and how can I watch?
The competition takes place at the Globe Arena in Stockholm, Sweden.
From the UK, you can watch it being streamed live on Eurovision's official YouTube channel, or you can catch it on BBC One at 8pm.
If you miss it tonight and you're desperate to catch up, it'll be on BBC iPlayer as well as Eurovision's YouTube channel.
How can I vote?
As is Eurovision tradition, you can vote for your favourite act by phone, and also by text.
You can also vote using the official Eurovision Song Contest app on your phone.
All 47 countries are allowed to vote, even though just 26 will perform.
Who are the hosts?
Last year's winner Måns Zelmerlöw will be hosting the show alongside Swedish comedian Petra Mede.
Sweden's Eurovision Song Contest entrant from 2014, Sanna Nielsen, will host Eurovision The Party where she'll have exclusive interviews and mingle with the acts as they wait out the rest of the night.
Who is representing the UK?
We're being represented by Joe and Jake, who met as contestants on The Voice UK and decided to become a duo.
They're hoping to win with You're Not Alone.
Pointless star Richard Osman will announce the results of voting in the UK live tonight. Last year TV chef Nigella Lawson read out the results.
Why is Justin Timberlake there?
For the first time in its 60-year history, US viewers will be able to watch the show live.
Justin Timberlake has been booked as the interval act - another first, since the interval acts are usually from the host country or particularly popular there, whereas Timberlake is a global popstar.
He follows acts like Riverdance, who shot to fame in the 90s after performing at Eurovision, and Aqua, who performed at the Contest in 2001.