Martin Short hasn't been seen much since his daughter Katherine's tragic death by suicide ... but he stepped out Friday evening for dinner with a talented Hollywood director.

The longtime comic actor made an appearance in Santa Monica ... wearing a neat black blazer over a button-down shirt.

Photogs got him jumping into a car driven by "Lost" co-creator J.J. Abrams, who is a longtime friend of Short's.

Short didn't seem his usual chipper self -- no smile on his face as he sat in the passenger seat.

Of course, Short hasn't had much to smile about recently ... on top of losing longtime friend Catherine O'Hara back in January, his daughter died from a self-inflicted gunshot wound last month.

Katherine -- who changed her name to Katherine Hartley to avoid being harassed by her social work clients -- revealed her struggles with mental health issues in the past.

After her death, Short and his pal Steve Martin postponed shows their comedic tour ... though they plan on getting back on the road April 11.

Katherine was 42.

RIP

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