Leno will sit on the bench in favour of Petr Cech, who was expected to start after playing in previous games in the competition.
But despite that Leno’s girlfriend, Sophie Christin, has been revelling in pre-match drinks at the Baku Olympic Stadium.
She has been pictured enjoying champagne at the venue’s VIP area ahead of the 8pm kick off.
Before then, she was also seen wandering around the Azerbaijan capital on Instagram, where she boasts 57,000 followers.
And there was also time for a stadium snap with the German shot-stopper yesterday.
They posed arm-in-arm at the ground, with Sophie captioning the shot: “I’d go anywhere for you.”
As displayed on her Instagram profile, the couple are absolutely smitten.
They have been dating for a number of years, with Sophie pictured with her man in London since his move to the capital.
Leno joined the Gunners last summer after making the switch from Bayer Leverkusen.
He has established himself as the number one choice in goal, with Unai Emery’s side finishing fifth in the Premier League.
If they beat Chelsea tonight, they will secure qualification to the Champions League.
The build-up to the final has been dogged by controversy, with the venue a 2,485-mile journey for English fans.
But despite warnings, fans have been told there will be bars to enjoy after the final whistle.
Ex-Daily Mirror reporter, Laure Hanna, said: “There are plenty of bars and clubs in the city centre, although they can sometimes be hard to find as many are underground.
“The most popular local beer is Efes on draft, which costs about £1.50 a pint.”