If you know anything about Eminem it’s that he always reps his city. Which is why it made perfect sense that the sometimes reclusive MC came out during the Thursday Night Football grudge match between the Baltimore Ravens and Cincinnati Bengals last night (Nov. 16) to talk about a Motor City NFL great.

The surprise appearance came during a promo for an upcoming documentary on legendarily elusive Detroit Lions running back Barry Sanders, who won the league’s MVP award in 1997 when he rushed for more than 2,000 yards during the regular season and also secured his second NFL Offensive Player of the Year hardware.

“I’ve seen every documentary on Barry Sanders that there is to see and I never walked away feeling like I knew why he walked away,” Em said in the brief clip from the film in which he talked about Sanders while sitting at the mixing console of a recording studio. “And I know that he walked away at a time when he could have broken every single record there ever was and ever will be.”

Sanders led the league in rushing yards four times during his 10-season career before shocking fans by retiring from football in 1999 at 31, at a point where he was 1,457 yards short of overtaking Chicago Bears great Walter Payton for the all-time rushing record. His shock decision to pull the plug is the subject of the film promoted during the Em appearance, the new sports doc Bye Bye Barry, which will world premiere at Detroit’s Fox Theatre on Friday night (Nov. 17).

“We had the greatest running back that ever played the game,” Em says in the official trailer for the film, which probes Sanders’ shocking decision to leave the league, still at his peak

According to the Detroit News, tickets for the screening will be available to Lions season ticket holders only, with Sanders expected to walk the red carpet along with Lions coach Dan Campbell, QB Jared Goff and other current team members. In addition to Marshall Mathers, the film features interviews with actor Jeff Daniels and a number of sports luminaries, including Jalen Rose, Calvin Johnson, Herman Moore, Chris Spielman, Patriots coach Bill Belichick, Emmitt Smith and ESPN’s Dan Patrick.

Bye Bye Barry will debut on Prime Video on Nov. 21.

Watch Eminem talking Sanders and watch the Bye Bye Barry trailer below.