In Marvel's Guardians of the Galaxy Vol. 2 movie, Stan Lee was seen talking to some bald blue aliens. Internet is on fire over this. Everyone is saying that Stan Lee's cameos in other MCU movies isn't a coincidence and he is actually an informant of Watchers.
Although it looks a great theory, I am not buying it. I mean, seriously? From when do Watchers need an informant? I haven't encountered them in comics so far, but when Galactus was about to attack Silver Surfer's original planet in cartoon, a Watcher appeared in the sky to warn them. Also, it should be obvious by the name that they can watch everything. If not, one Google search is enough.
On the other hand, it is possible that MCU version of Watchers can't see everything by themselves and they indeed need an informant. Has it been officially confirmed or referenced or shown in the canon that those blue bald aliens were Watchers? They looked more like Oa's guardians than Watchers.