England plan to take the knee ahead of all their games at Euro 2020, with the squad doing so to peacefully protest against discrimination, injustice and inequality.
There are fears, however, that supporters may boo the gesture - as was the case when England did it ahead of their warm-up games in Middlesbrough earlier this month.
Some fans believe taking the knee has become political and voice their displeasure at this by booing the action.
England and Southgate have continually stressed they are not making a political statement, with the FA reinforcing that again on the eve of the Three Lions beginning their Euro 2020 campaign against Croatia at Wembley on Sunday.
The FA have urged fans to consider what impact it will have on the players if they are booed and called for unity among supporters too.
“Tomorrow, our England senior men’s team will begin their EURO 2020 campaign at our home, Wembley Stadium,” the FA said in a statement.
“Major tournaments don’t come around often and when they do, it’s an opportunity to unite friends, families and the country. This collective support is what spurs our team on during challenging moments and it gives them the best chance of succeeding.
“As the team has reiterated many times, they will collectively take the knee ahead of their fixtures during the tournament.
“They are doing this as a mechanism of peacefully protesting against discrimination, injustice and inequality. This is personally important to the players and the values the team collectively represents.
“This gesture of unity and fighting against inequality can be traced back as far as the 18th century. It is not new, and English football has made it very clear that it does not view this as being aligned to a political organisation or ideology. There can be no doubt as to why the players are taking the knee and what it represents in a footballing context.
“We encourage those that oppose this action to reflect on the message you are sending to the players you are supporting.
“Please respect their wishes and remember that we should all be united in the fight to tackle discrimination. Together.
“They will do their best for you. Please do your best for them.”