Not much of a spoiler, but I'll be on the safe side..
This article was found here: http://inq.philly.com/content/inquirer/2001/03/13/magazine/SHIS13.htm
"NBC: Matthew Perry will make it to 'Friends' wedding on time
The wedding's on, Friends fans.
Matthew Perry (Chandler) will return from rehab in time to marry Monica (Courteney Cox Arquette) on the season finale, according to an NBC executive who spoke yesterday on condition of anonymity.
NBC was informed last week that Perry, 31, who entered a drug-and-alcohol rehab facility in late February, would be back on the set for production of the hour-long May 17 finale in which he and Arquette tie the knot, the executive says.
Shooting on the wedding episode will begin in about two weeks. Currently on production hiatus, Friends returns to work Tuesday before wrapping its seventh season March 31.
Viewers will be hard-pressed to have even noticed Chandler's absence, however.
March 1 and 8 were repeats. Six of eight original remaining episodes are in the can, and the pre-rehab Perry appears in the first two - to air Thursday and March 29. (March 22 is a repeat.)
Having been released by NBC to work on his big-screen flick Serving Sara, with Elizabeth Hurley, Perry had already shot scenes for several episodes. Including the May 3 segment featuring a lip lock between Jennifer Aniston (Rachel) and guest star Wynona Ryder.
Perry's Chandler is included in the third and fourth of the six already-produced episodes, but his scenes will be inserted sometime before the segments air.
Perry is expected to be on the set for the final two of NBC's 24-ordered episodes. Friends is completing the first season of a two-year renewal.
NBC had no comment other than to wish Perry well."