Tyrese -- Hooks up the Nanny ... With a BRAND NEW CAR!!!

Tyrese Gibson reduced a grown woman to tears -- surprising his longtime nanny with a sweet new ride!

TG handed over the keys to a black Audi sedan Monday ... totally shocking the woman a la Oprah -- and the video is pretty awesome. He says she's been taking care of his 7-year-old daughter Shayla most of her life ... so she's earned the bonus.

Toward the end of the clip there's a shot of her old car. We'll just say ... serious upgrade.

We just hope Tyrese learned from Oprah, and paid the taxes for her.