The game will be played at FC Strání Stadium on Saturday 5 September, kick-off 2pm UK time.
Jan has been a regular with the Czech age groups in recent years, earning 45 caps at Under-15 to Under-19 level, scoring five goals. Nine of those caps have come with the Under-19's who he helped into the Elite Qualifying Round for this summer's postponed European Championships.
Jan made 19 appearances for Thomas Frank's Bees last season, 16 of them in the Sky Bet Championship, setting up Ollie Watkins for our third at Bristol City on Boxing Day.