Now, this is a far cry from Zack Morris!

Mark-Paul Gosselaar has had his dark brown beard for quite a while now -- for months, in fact, ever since he started filming and promoting his new show, Pitch -- but Monday night was the first time we audibly gasped at it.

EXCLUSIVE: Mark-Paul Gosselaar Doesn't Want His Son to Follow in His Saved by the Bell Footsteps

Not that it's a bad look, mind you. Rather, it's because, despite knowing that the beard is on full display on the Fox drama, the 42-year-old actor was practically unrecognizable as he walked the red carpet at the Men's Fitness Magazine's Annual Game Changers celebration in West Hollywood, California, with his wife, Catriona McGinn.

Just for funsies, here's what he looked like with just a little scruff last year:

And here's a close-up of his straight-up mountain man beard last night:

WATCH: Why You'll Fall in Love With Pitch Star Kylie Bunbury

It's like a whole different person. We're not gonna lie, though -- we kind of dig it. It's like he's… saved by the beard. (Get it? Right, yes, we're burying out heads under a blanket now…)

Now that we're all staring, let's take a journey through the life of MPG's main mane.

In January, when Gosselaar and McGinn brought their sons, Michael and Dekker, to the Monster Energy Supercross Celebrity Night at Angel Stadium of Anaheim, we still had no idea what we were in for. But, oh, the foreshadowing:

The first hints of legit facial hair then went golfing in February:

EXCLUSIVE: Mark-Paul Gosselaar Is Back in the Director's Chair and This Time, He Has a Plan

One month later, he already had a full-grown beard that even this lion seemed impressed with:

In April, the beard experienced a hockey date night.

Gosselaar got a sweet trim at The Art of Shaving in Sherman Oaks, California, in June:

It became very clear at this "team meeting" in July that the beard was here to stay:

PHOTOS: The Most Adorable Celebrity Dads

Luckily for this father of four, his eldest daughter, Ava, appeared to approve when they spent the day at Dodger Stadium just last month.

Yet, despite all these photos, we still can't get over the beard. THE. BEARD.

ET's Sophie Schillaci caught up with the California native at the Men's Fitness event, where he didn’t talk about the facial hair he grew for the show, but he did talk about his insanely strict new diet regimen for it called ketogenic.

"It's basically paleo, but even worse -- or better, depending on how you look at it," he explained. "It's pretty hard, especially for us, because we're so active. We're doing this whole baseball thing. We're training sometimes three hours a day. Unbelievably [with] keto, you don't do any carbs. It's all animal proteins and fats and vegetables and things that have low carbs and no starches. You have energy. Your body is pumping out the fat."

Though it's tough to stick with such a strict diet, he said that his "wife is a saint," and helps him maintain his proper food intake.

"She cooks meals for me, for the kids, for herself, and we have cheat days every once in a while," he admitted.

His favorite cheat day meal? "Pizza and ice cream," he said.

EXCLUSIVE: Tiffani Thiessen Talks Mini-Saved by the Bell Reunion With Mark-Paul Gosselaar

Earlier this year, Gosselaar admitted that the beard is, in fact, to take him as far from his iconic Saved by the Bell role as possible, a choice he credits to Pitch creator Dan Fogelman.

"Dan was really the first to say, 'I want to break that. I don't want people to recognize you right away,'" Gosselaar told reporters at the 2016 TCA Summer Press Tour. "That's the beard."

Find out more about his new role and what he told ET about his 12-year-old son, Michael, following him into the family business in the video below.

Related Gallery

Stars Who Love Sports