The Palace pair will join up with the national side on their trip to Slovakia for the first round of UEFA European Championship qualifying.
The Young Lionesses will take on Slovenia and Denmark either side of a clash with hosts Slovakia.
Midfielder Guyatt and goalkeeper Negri have been part of a Palace Women squad in fine form so far this season, as they sit just a point off top having won three of their opening four games in their hunt for promotion.
All times BST.
England U19s - Guyatt and Negri
- Weds, 5th October: England U19s v Slovenia U19s (11:00)
- Sat, 8th October: England U19s v Slovakia U19s (16:00)
- Tues, 11th October: Denmark U19s v England U19s (14:00)