The legendary rapper is a big Detroit Lions fan ... and with the team hosting a home playoff game tonight for the first time in 3 decades (1994), Eminem sent a message to the 35-year-old former #1 overall draft pick ahead of the highly anticipated Super Wild Card matchup.

"Stafford, what'd I say? You owe me this favor, bro. I was there for you when you won it. I was there for you. I was right there. I rapped for you Stafford, bro, I rapped for you. Can you just let us have this one? Just this one!"

When Em says he "rapped for" Matt, he's referring to Super Bowl 56 at SoFi Stadium in 2022 ... where Marshall (along with Dre, Snoop, Mary J., and 50) performed one of the best halftime shows in SB history.

On the field, Stafford's Rams beat the Bengals, 23-20 ... and Em showed love for the former Lions star.

Of course, before he ever played a down as the Rams QB, Stafford broke into the league as a Lions star in 2009 ... when he was drafted with the first overall pick.

Stafford, after 12 seasons in Detroit, was traded for now-current Lions' signal-caller Jared Goff, in 2020.

Goff's played some of the best football of his career since leaving SoCal, and led the Lions to a 12-5 record this season. It's the rare trade that has worked out great for both organizations.

Eminem aside, anticipation of Matt's return to the Motor City has become a bit of a contentious topic ... with some fans calling for a boycott of his Lions jersey at Ford Field, which didn't sit well with Stafford's wife, Kelly.

As for Sunday's game, it's expected to be incredibly close ... so you can't fault Em for trying to get an advantage!

The Lions have never won a Super Bowl (they won 4 championships before the SB era), and haven't won a playoff game since January 1992.