The 19-year-old has agreed a four-year contract and the deal also sees Charlton enter a three-year collaboration with the club.
Charlton manager Alan Pardew said: "Martin's a great prospect and we think very highly of him.
"It's going to be a big step-up for him to this level of football, but he's of a good age and we feel he'll progress very quickly with us."
Source: www.cafc.co.uk