Hey,
Simon Grace is played by Freddie Highmore. Freddie also plays Jared Grace.
Freddie highmore
Sarah Bolger.
Freddie Highmore (who plays Jared and Simon) turned 17 on 14 February 1992. Sarah Bolger (who plays Malory) turned 18 on 28 February 1991.
In "The Spiderwick Chronicles," the secret door to Arthur Spiderwick's study is hidden within the walls of the Spiderwick estate. It is concealed behind a panel that can only be revealed by solving a riddle or using specific knowledge of the house. The door leads to the study where Arthur's extensive research on magical creatures is kept. This hidden entrance plays a crucial role in the adventure of the Grace children as they explore the magical world.
Freddie plays double role...he plays Jared and Simon alone
If you mean the actor who plays the part of Jared Grace in the movie, then the actor's name is Freddie Highmore.
Arthur Spiderwick is a fictional character in the children's book series "The Spiderwick Chronicles". He is a naturalist who studies and documents magical creatures. His field guide is sought after by both curious children and malevolent creatures in the series. Arthur’s work plays a central role in uncovering the hidden world of faeries and protecting it from harm.
Debra Messing plays Grace Adler on Will and Grace.
Skandar Keynes plays Edmund Pevensie in all three "The Chronicles of Narnia" films.
Logan Lerman is who plays Simon.
Grace Phipps plays Lela.
Matthew Gray Gubler plays Simon in the movie "Alvin and the Chipmunks".