Julie Andrew and Maria Von Trapp.
And in this video, they not only visit and chat, but even sing together! It's a little bit of Alpine yodeling, as Maria gives a lesson to her doppleganger in how to do it properly, and the result is a charming counterpart duet.
The Von Trapp family actually eventually came to live in the United States, where they ran a ski lodge (hey, what did you expect?!) for many years. Several members of the family (generations later, great-grandchilden of the Baron -- children of Kurt, I believe) still perform together as the Von Trapp Family Singers.
This clip comes from a variety show that Julie Andrews did in 1972-73. There's actually a much long video of the appearance, that includes a sit-down conversation. Unfortunately, the audio quality for it is terrible, with an annoying hum all the way through. I'll include it, for those who want to watch for the sense of history -- it's enjoyable, but not for everyone.
Okay, for those history buffs who would like to see more of this, here are those eight minutes of the two "Sister Maria's" -- complete with Chinese sub-titles, no less! (Or Japanese. Or Korean, or...well, whatever, you get the point.) The sound is definitely not alive with music, as I said -- it's terrible, thanks to a relentless humming sound. But it's still a fascinating eight minutes. Know that though it says "part 1 of 2," I haven't been able to track down any "part 2."