Jack and Chrissy reference in Friends by Chandler

Question

In the Friends episode The one with two parties, while Mr. and Mrs. Green both came to the party and Monica was panicking why did Chandler say:

what would Jack and Chrissy do?

Who were Jack and Chrissy?

Here is the full context:

Mrs. Green: Oh well thank you. Such a gentleman. Thank you. (Chandler takes the hot pink coat and grimaces at it) Ahh, it all looks so nice, so festive, all the balloons... (Chandler, remembering that Joey and Mr. Green are in the bedroom, throws her coat in a cupboard) The funniest thing happened to me on the way here. I was...(Joey peeks out)

Phoebe: (cutting Mrs. Greene off) Ha-ha, that's great, ha-ha. I can't wait to hear the rest of it, ya know, but I really have to go to the bathroom so... Hey, come with me. Yeah, yeah, it'll be like we're gal pals, ya know, like at a restaurant Oh, it'll be fun, c'mon. (They go in the bathroom)

Monica: Oh my God, oh my God, oh my God.

Chandler: Ok, think, what would Jack and Chrissy do?

Answer 1

It's an homage to Three's Company:

Chrissy Snow (on the right) and Jack Tripper (in the middle) are two characters from the show.

Note: This isn't the first reference to Three's Company in the show. In Episode 1.02 (The One with the Sonogram at the End), while watching TV with Phoebe, Chandler does sarcastically remark:

Chandler: Oh--I think this is the episode of "Three's Company" where there's some kind of misunderstanding.
Phoebe: Then I've already seen this.

Answer 2

Jack and Chrissy were two characters in the 70's/80's hit SitCom Three's Company, played by John Ritter and Suzanne Sommers respectively. The characters were often finding themselves in uncomfortable or compromising situations.