Brentford will play Benfica on Thursday 25 July in a friendly at Estádio da Luz (8pm kick-off) as part of a pre-season trip to Portugal.
This fixture is open to supporters and ticket information, including sales windows, will be announced this week.
Benfica are the most decorated club in Portugal, having won 83 domestic trophies and two European Cups.
Roger Schmidt’s side finished as runners-up to Sporting CP in the 2023/24 Primeira Liga.
The Bees will spend time in Portugal as part of a training camp this summer, in preparation for the 2024/25 Premier League campaign.
As well as taking on 38-time Primeira Liga champions Benfica, the west Londoners will play a behind-closed-doors friendly against Estrela da Amadora on 30 July.
As revealed last month, Brentford will play pre-season friendlies against Sky Bet Championship side Watford (Saturday 3 August) and Bundesliga outfit Wolfsburg (Friday 9 August).
Thomas Frank’s side are also set to face National League Sutton United in a behind-closed-doors game in July.