Drake Bell -- I Got Two Words for Amanda Bynes

Nickelodeon star Drake Bell has a two-word message for his former co-star Amanda Bynes ... and he tells TMZ, he wants to deliver it personally just as soon as she's allowed to have visitors.

Bell -- who co-starred with Bynes on "The Amanda Show" from 1999 to 2001 -- was at LAX when he stopped to talk about Amanda ... and our story that she would be released from rehab -- and back with her family -- by Christmas.

Drake says he reached out to his good friend a while ago ... and "as soon as she's allowed to make contact again I'd like to make sure she's alright."