Henderson played in the second half of England’s 1-0 win over the Czech Republic that locked in their place in the last 16 as group winners on what was another step forward after injury.
It set up an intriguing evening on Wednesday as they watched the dramatic events of Group F unfold, where they were matched with all four teams at one point or another.
But a late rally from Germany would seal their runners-up place in Group F to set up a Wembley clash with England, pitting the Liverpool boss and his captain against the other.
And the German had a quick message to send to Henderson when the schedule was confirmed.
“Yes, he has texted,” Henderson admitted of his German boss with a wry smile. “As soon as the final whistle went he just sent us a smiley face emoji!”
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There’s no questioning where Klopp’s allegiances lay, but he will no doubt be eager to see Henderson come through unscathed should he feature.
Since his groin injury in February, Henderson has played just 90 minutes in total in two separate halves for England this summer.
And the 31-year-old is feeling “really positive” ahead of England’s must-win match against Germany after an extensive rehabilitation process.
“The toughest part of being an athlete is dealing with injuries. It wasn’t easy, it was tough to go through that period. But you always seem to come out of it stronger,” Henderson said.
“The amount of work you’re doing in the gym and the amount of training you do so I’m in a pretty good place. I feel physically very good because I’ve had a long period of training.
“It was great to get on the pitch finally in a competitive game the other night and get 45 minutes under my belt which I felt good in.
“I feel really positive in the situation I’m in, and hopefully, I can keep contributing to the team.”