Person contacted to clothe Eddie's outside behind trailer (9)

I haven't cracked this one yet — but the brilliant team at Fifteensquared have:

DRESS (as a verb = to clothe) + outer letters of E [ddi] E , after (behind) AD (abbreviation for advertisement; trailer = a short film advertising a longer one, or the television equivalent). The person to whom a letter, package or electronic message is sent.