"Stranger Things" star Gaten Matarazzo is undergoing surgery for a rare bone disorder.
On Wednesday, the 17-year-old actor posted a selfie in which he gives a thumbs up to the camera.
"Surgery number 4! This is a big one!" he captioned the snap. "To learn more about Cleidocranial Dysplasia and how you can help those with the condition you can go to ccdsmiles.org."
CCD is a birth defect that affects the growth of the bones and teeth.
Gaten's post prompted several of his "Stranger Things" costars to comment with well wishes.
"Good luck love!!! sending my love gate," Millie Bobby Brown said. Carla Buono, wrote, "Sending you supernova good vibes. Love you." Matty Cardarople, who stars as Keith on the show, wrote, "You're super brave and strong man. Good vibes to you."
Gaten has previously acknowledged getting several surgeries on his mouth.
"There's a one in a million chance that you have of getting it — most likely you get it from a parent, but it just happened for me," he told People magazine in 2016. "I have a very mild case so it doesn't affect me as much, but it can be a very difficult condition to have."
He does, however, think that it affected his career.
"It's one of the reasons why I haven't been getting roles, because of my lisp, and the teeth situation, and my height," he said in 2018 while appearing on "The Doctors." "That affected pretty much everything. I would go three times a week for auditions all the time and get constant 'no.' "
Ten months ago he told his social media followers that he was getting his third surgery.
"Yo dudes! A little pre-op pic before my oral surgery today," he said in March 2019. "One step closer to having my own real teeth eventually. @ccd_smiles."