Chaplin's The Circus is one of those films that just bubbled up on the queue. It features the Tramp stumbling into a failing circus, and being mistaken for a clown - the only funny thing in the show. The evil ringmaster hires him as a custodian, and lets the audience laugh at him. The gag here is that Chaplin can't be funny when he tries - only when he thinks he's a janitor.
Meanwhile, he is falling in love with the ringmaster's daughter. But she loves the new tightrope walker.
There are some good gags in this, especially a hilarious and technically challenging Mirror Maze routine. But it is certainly less than a laugh a minute. It also has some sweet romance and pathos. All in all, I'm afraid I have to rate this as lesser Chaplin. Of course, considering that Chaplin went through a bad divorce, IRS troubles, a nervous breakdown, and had his studio burn down while making it, allowances can be made. Still, not his best work.
The DVD release does feature Chaplin from 1970 singing the theme song.