Wild Strawberries stars Victor Sjostrom, Sweden's most notable director before Bergman

Orson Welles has a number of acting credits in other peoples' movies. I think the oddest one is in Pasolini's short satirical film La Ricotta, where he plays an arrogant American director and his voice is dubbed over completely in Italian (probably as satire of the practice, which was common in Italian movies at the time).