Bruno Mars Honoring Cardi B Nightly on Tour, As Promised

Bruno Mars is a man of his word when it comes Cardi B -- he's honoring her every night on his tour ... with a pretty epic drum solo.

So far, he's played just over a handful of shows on the 24K Magic World Tour, which Cardi pulled out of last month. Even though she's not there, Cardi's huge hit, "Bodak Yellow," is featured every night when Bruno himself gets behind a drum kit.

Earlier this week, he played in Philly and the crowd ate up the combo of Cardi's voice and track with Bruno's 90-second solo ... complete with a badass light show.

Remember, Cardi said she needed more time to adjust to motherhood. She also said doctors told her it wouldn't be a good idea to bring baby Kulture on the road ... so she bowed out.

Bruno sent a message to Cardi after her announcement, saying he completely understood putting family first and promised to play "Bodak Yellow" every night in her honor.