Penalty (Hidalgo-Clyne)published at 19:48 British Summer Time 1 May 2015
The ball is around 35 metres out but nerves can do funny things to players. Not to Sam Hidalgo-Clyne, though, who calmly slots the ball through the posts. Edinburgh lead.
FT: Edinburgh 13-19 Gloucester
Twelvetrees try puts Gloucester in front
Laidlaw kicks 14 points against former club
Meakes sent off for high tackle with 17 minutes left
Ford touches down for Edinburgh
Steve Marshall
The ball is around 35 metres out but nerves can do funny things to players. Not to Sam Hidalgo-Clyne, though, who calmly slots the ball through the posts. Edinburgh lead.
Good early pressure from Edinburgh, who are awarded an early penalty in kicking range for Gloucester not releasing their man on the floor.
French referee Jerome Garces blows his whistle, Edinburgh fly-half Phil Burleigh kicks is high and we're under way.
The two sides are on the pitch and are greeted by a wall of noise. There's some tense faces out there. Kick-off is only moments away.
A Gloucester win tonight would make then the fourth English club to have won the Challenge Cup twice or more.
The others? Harlequins, Sale and Northampton. As we know, Edinburgh would be the first Scottish side to win a European crown.
As well as following live text of tonight's game, you can also listen to the action.
We have a choice of commentaries for you too, with BBC Radio Scotland and BBC Radio Gloucestershire both covering the game and offering their distinctive perspectives.
Just click on the live coverage tab and make your choice.
Edinburgh head coach Alan Solomans says it would be a "wonderful, wonderful achievement" if his side could win tonight's final and become the first Scottish side to lift a European trophy.
"To win a competition of this nature would be incredible," Solomons told BBC Scotland.
"The big thing is for us to deliver a performance, possibly our best performance of the year.
"We have to be at our absolute best to do it. We're up against a strong side but we have a good team, there is a good team spirit and everyone's determined to see this through."
As you'll have gleaned from the team news, there's a familiar face in the Gloucester ranks for Edinburgh this evening.
Cherry and Whites and Scotland scrum-half Greig Laidlaw left his hometown club to move to Kingsholm last summer.
And the 29-year-old is hoping his old team-mates return north disappointed.
"They've progressed since I left," said Laidlaw. "It's taken time under Alan Solomons but, credit to him, he's done a good job. The players are all playing very well and they deserve to be in the final.
"I know how desperate Edinburgh will be to win the final and be the first Scottish team to win this trophy, but I want to win things playing for Gloucester."
Gloucester's official account on Twitter:, external Bit of a chilly breeze in the air tonight. Bad night to be a cheerleader….or in a kilt! #GLOSvEDIN
Andrew Priestley:, external Edinburgh have been the whipping boys in recent seasons, great to see them in a final but Gloucester will have too much for them.
The Stoop is filling up and the Gloucester crowd are already making a lot of noise.
'"Glaawwwster" is the cry. It's sounding like a home game for the Cherry and Whites.
There's only 10 minutes until kick-off.
Gloucester rested a number of players for the Premiership fixture against Newcastle, with former Edinburgh scrum-half Greig Laidlaw one of those coming in to face his former club.
Billy Twelvetrees captains the Cherry and Whites, while Wales duo Richard Hibbard and James Hook also return.
Gloucester: Sharples; May, Meakes, Twelvetrees (capt), Purdy; Hook, Laidlaw; Wood, Hibbard, Afoa, Savage, Palmer, Moriarty, Kvesic, Evans.
Replacements: Dawidiuk, Thomas, Puafisi, Galarza, Rowan, Robson, Burns, McColl.
Edinburgh welcome full-back Greig Tonks back into their side to face the Cherry and Whites.
He is one of two changes made by head coach Alan Solomons, who also brings Cornell Du Preez in at flanker.
Edinburgh: Tonks; Fife, Beard, Strauss, Visser; Burleigh, Hidalgo-Clyne; Dickinson, Ford, Nel, Bresler, Toolis, Coman (capt), Grant, Du Preez.
Replacements: McInally, Sutherland, Andress, McKenzie, Watson, Fowles, Heathcote, Brown.
So, that's how the two sides made it to The Stoop. Now seems a suitable time to take a look at this evening's line-ups.
A one-sided 45-16 Murrayfield victory over Newport Gwent Dragons earned Edinburgh their spot at the Twickenham Stoop for this evening's final.
Gloucester's passage was less straightforward as they needed two late tries to beat Premiership rivals Exeter 30-19 and reach their first European final for nine years.
Gloucester were the first team through to the last four after holding on to overcome Irish side Connacht 14-7 at Kingsholm, courtesy of tries from Charlie Sharples and Billy Meakes.
Edinburgh went through a range of emotions as they finally saw off London Irish 23-18 at the Madejski Stadium.
They blew a 16-0 lead to trail 18-16 soon after half-time, before finally winning the game thanks to Fraser McKenzie's try.
Even then there was late drama as the Television Match Official chose not to award Irish a match-winning try with the last play of the game, ruling that David Paice had been held up.
Both sides made serene progress through their pools to reach the knockout stages.
Gloucester finished with the best record of all the teams, winning a perfect six from six to top Pool 5 by 13 points.
Edinburgh lost only one game as they won Pool 4 - going down 21-19 at Lyon Olympique.
Twelve months ago, Stephen Myler kicked 20 points to help Northampton Saints overcome Bath and win their second Challenge Cup.
Phil Dowson and Ben Foden also ran in tries as the Jim Mallinder's side completed the first leg of their league-and-cup double.
So how are you feeling Edinburgh and Gloucester fans? Butterflies in the stomach or are you super confident this is going to be your night?
However you're feeling - or if indeed you don't support either club - we'd love to hear from you during the course of the evening.
Get in touch by using #bbcrugby on Twitter.