'Magnum P.I.' Sneak Peek: Rick Believes Magnum and Higgins Are 'Totally Doing It' (Exclusive)

Is Magnum and Higgins' secret romance about to be discovered?

Are Magnum and Higgins about to get found out?

Magnum P.I. spices things up on Sunday's episode, titled "Dead Ringer," when Magnum (Jay Hernandez) and Higgins' (Perdita Weeks) secret romance is on the precipice of becoming public knowledge as team members begin to suspect they may be up to some extracurricular activities. 

ET exclusively premieres a sneak peek from the hour, which kicks things off with Magnum and Higgins enjoying a very domestic morning at home on a rare off day. With nowhere to go and no cases to solve (yet), Magnum floats the idea that they stay home instead of going out for the day to, ahem, get a little frisky in the bedroom.

At that exact moment, Rick (Zachary Knighton) storms in and is caught off-guard seeing Magnum and Higgins together. "Oh, hi... Hello, hi... hello, hallo," Rick says, trying to act cool.

"Rick, are you having a stroke?" Higgins asks after his unusual greeting.

"I don't think so... Wait, no," he proudly confirms, before grabbing his things to head into the office. But he makes sure Magnum and Higgins know they'll have the place to themselves -- without any interruptions -- for basically the entire day. Wink, wink. 

Of course, after Rick leaves, Magnum and Higgins can't keep their hands off each other in a steamy make-out session before she stops and asks one probing question, "Do you think he was acting a little bit... weird?" Magnum's response is pretty spot-on, even though he's too naive to see past it: "It's Rick, that's pretty on brand."

Cut to Rick sharing his suspicions with anyone who will listen as he declares, "I'm telling you, they're totally doing it!" Watch the clip above to watch the full scene.

According to the episode synopsis, Katsumoto’s (Tim Kang) hearing date has arrived and he will learn if his career in law enforcement is over for good or not. Magnum and Higgins are hired to investigate a man their client believes committed murder. Rick’s suspicions grow on their relationship. 

Magnum P.I. airs Sundays at 9 p.m. ET/PT on NBC.