Aaron Cresswell has extended his stay at West Ham by signing a new five-year contract.
Phil Jones has signed a new deal with Manchester United which keeps him at Old Trafford until June 2019.
The 23-year-old has signed a three-year contract at The Valley and becomes the Championship club's ninth new recruit of the summer.
Tucudean has flown out to Charlton's training camp in Spain and could feature in their friendly matches against a Gibraltar XI on Wednesday evening and Atletico Clube de Portugal on Saturday.
He follows Yoni Buyens, Igor Vetokele, Franck Moussa, Andre Bikey, Tal Ben Haim, Johann Berg Gudmundsson and youngsters Zak Ansah and Kurtis Cumberbatch in moving to The Valley this summer.