The League One club announced the signing this afternoon on their website.
Dasilva will join the club when the January transfer window opens on Sunday.
The England Under-19 international trained with his new team-mates today.
“I’m not the tallest but I’m very quick and this is the next step for me in my development as a player”
Chelsea starlet Jay Dasilva
He is Karl Robinson’s first signing since taking over in November.
And the Chelsea ace is delighted to complete his move in search of regular first-team football.
Jay Dasilva said: “I’m delighted to sign here on loan until the end of the season and I cannot wait to get started.
“This is my first loan move, so I’m itching to get going and I’m looking forward to getting familiar with everything around here.
“I see myself as an attack-minded player. I’m not the tallest but I’m very quick and this is the next step for me in my development as a player.
“I think that Charlton is the right place for me to take that step.”