Carlos Gómez, who plays Julio in this episode, was in the film Fools Rush In (1997) with Matthew Perry from the same year.
Carlos Gómez, who plays Julio in this episode, later starred as Sam (the director) in the spin-off series Joey (2004).
Incidentally, in an episode whose title and plot are about jealousy, Gunther wears a bright green shirt as he watches Rachel and Ross on the couch - he's literally "green with envy."
Joey auditions for a role in a Broadway adaptation of "A Tale of Two Cities". An actual adaptation was produced on Broadway in 2008.