Many thanks to @Clermont1 for tweeting the link to his his instagram photo. He tweeted the following:
When Keanu Reeves is the angel behind you at The National show. LA.
On instagram he posted two photos. One is from The National concert and the other is of Keanu sitting in the background of what looks like a restaurant or hotel lobby. The location on the instagram photos is The Roosevelt Hotel. The National concert was at the Hollywood Bowl last night, October 11. It is not clear if Keanu sat behind him at the concert and then they ran into him again at the The Roosevelt. Based on the length of Keanu’s hair, the photo looks recent.