Just who was that guy sitting on the Mariners bench, the odd fellow with the bushy mustache, shades and a hoodie?

Wait a second — it was Ichiro!

Now a team executive, Ichiro Suzuki donned a Bobby Valentine-style disguise and sneaked into the Seattle dugout Thursday to watch a bit of the action at Yankee Stadium.

Exactly as he hinted, in fact.

“He was perfect. I never would have known it was him,” Valentine texted to The Associated Press.

Officially, Suzuki isn’t allowed to be in the dugout during games under Major League Baseball rules. The 44-year-old outfielder with 3,089 career hits came off the Seattle roster in early May and moved into the team’s front office as a special assistant to the chairman.

Suzuki has been taking part in pregame drills and batting practice in a role similar to a coach. But he’s required to leave the bench when games begin, and that’s when he takes his place in the clubhouse — usually, anyway.

This time, in a ballpark where he played for parts of three seasons, Suzuki got a much closer look.

AP photographer Bill Kostroun spotted Suzuki with his face nearly covered by a fake mustache, sunglasses and a gray hoodie drawn tight over his head during in the first inning as the Yankees hit a pair of two-run homers.

Suzuki sat in the middle of the dugout, in the back row, in his shorts and occasionally crouched down while the Yankees swung away. He was gone by the second inning of Seattle’s 4-3 loss that completed a New York sweep.

The 10-time All-Star hasn’t officially retired, and there’s speculation the Japanese great might play when the Mariners open the 2019 season in Tokyo with a two-game series against Oakland.

This was Seattle’s only trip to Yankee Stadium this year, and maybe Suzuki wanted a final look at the ballpark. Or perhaps he was just showing off his playful side.

On the day it was announced Suzuki was moving into his new position, he predicted this might happen.

“During the game I will be doing the same preparations I’ve been doing the entire time. Nothing is going to change for me that I did as a player,” Suzuki said at the time. “But I can’t say for certain that maybe I won’t put on a beard and glasses and be like Bobby Valentine and be in the dugout.”

In 1999, the excitable Valentine was ejected from a game he was managing for the New York Mets. He was tossed in the 12th inning, but soon put on a fake mustache and sunglasses and returned to the dugout in disguise.

Valentine was later suspended for two games and fined $5,000.

The longtime manager liked Suzuki’s creativity.

“One of the biggest honors of my life,” Valentine said. “I was going to send him a set, but he didn’t need it.”