Considering the jerrybuilt way in which this was conceived/assembled (incorporating documentary footage of Doug & Mary's Russian vacation into fiction narrative without their knowledge), the result is pretty seamless.
But while the Hollywood superstars' presence is clearly the hook, the movie belongs entirely to Igor Ilyinsky, then near the beginning of a very long and popular career as a stage/film comic actor. I didn't know anything about this guy before, but he's really a gifted physical comedian--more in the manic, rubbery vainglorious-goofball mode of Jim Carrey than Chaplin, Keaton, Lloyd or other 1920s contemporaries.
Pickford looks lovely doing the goodwill-ambassadress thing in her scenes--which culminate in a little comic bit she was somehow persuaded to perform with Ilyinsky--while Fairbanks (who briefly demonstrates his famous athletic prowess) looks very, very tanned. Like, George Hamilton tanned.
The public hysteria that ensues after our hero has actually been touched by a visiting Hollywood celebrity is just as funny as his earlier tribulations (which include a bizarre stress- test medical exam). I saw this in a good DVD transfer (albeit with untranslated Russian titles), suggesting perhaps it's been restored for imminent DVD release. (No, I can't get you a copy--it was a press screener in advance of a single-showing big-screen revival--but quite likely the film is going to be more accessible soon, I'd guess.)
I would be very happy to see any other movie that gave Igor Ilyinsky an equal showcase, though it's hard to imagine one that would be this fast-paced, inventive, and American- influenced in its brash slapstick style.