Selena Gomez Makes 'Diddy' Slip During Charity Event in L.A.

Selena Gomez made a tiny slip during a speech at her L.A. charity event Thursday night --- and it had to do with Diddy!

The singer/actress was dressed to the nines as she stood at a podium speaking to a few hundred guests at her Rare Impact Fund Benefit at nya Studios West in Los Angeles when things went a little sideways.

At first, everything was cool ... Selena addressed the mission of her charity, which works with the Didi Hirsch Mental Health Services (DHMS) to help prevent suicide among youths.

She then flubbed her next line while introducing the executive director of Didi Hirsch to the stage, accidentally saying Diddy because the names are similar.

Check out the clip ... the crowd picked up on Selena's error and started laughing.

Selena cracked a smile, realizing what she had just said and immediately corrected herself while also apologizing ... "I really am sorry."

Selena then invited the exec Lyn Morris and another DHMS executive to the podium and they greeted each other with hugs.

Soon, Diddy was all forgotten and the event went forward with no other issues.

As we reported ... Diddy was arrested by the feds in September and indicted on charges that include racketeering and sex trafficking. The music mogul pled not guilty but remains in jail after twice being denied bail.