The pair are among the 26 names that the Three Lions boss has picked for the tournament in Germany, which gets under way in just over a week’s time.
Fellow Red Harry Maguire was part of the provisional group with his aforementioned club colleagues but has not been selected, having been unable to overcome the calf injury that kept him sidelined for the final weeks of the season.
Mainoo’s inclusion means he will be going to his first major international tournament, following a breakout campaign for the Reds.
The 19-year-old midfielder became a regular in Erik ten Hag’s XI after his first Premier League start in November and was rewarded for his performances with a first senior England call-up in March.