A$AP Rocky had to miss out on the Berlin Film Festival today due to his ongoing assault trial in L.A. ... but his new film costar Rose Byrne and the director are filling his absence with praise!!!

The rapper stars with Byrne in the upcoming flick “If I Had Legs I’d Kick You” ... and according to Variety, she and director Mary Bronstein had nothing but good things to say about his performance.

Bronstein revealed she wanted "non-traditional actors for the supporting roles," which opened up the space for Rocky to play a motel superintendent.

The director also says she and Rocky are in constant communication ... hoping for the best, relating he was a pleasure to work with, for herself and the crew on set.

Byrne called Rocky a "true renaissance man" and peeped his swag ... "He lives and breathes art and fashion and film and he has such respect and reverence for all the genres and all artists. I was totally disarmed by him.”

Rocky won't have to wait long to know if he'll be able to start promoting the flick, which premiered at Sundance in January ... jury deliberations begin Tuesday morning!!!