I met Tommy Cooper backstage at the Sheffield Fiesta Club. I was there as a bar man, and had to stock the Star Dressing Room from the main Lounge Bar. This was the 1970's (man). When I say "met him" he did speak to me, he asked me quite politely to get out of his way. [This happened also with Gene Pitney and Moira Anderson in exactly the same location in the club..] I recall Tommy C spent a lot of time after the shows in the restaurant area, and not just eating, he then hit the bar... there was a lot of booze around in those days... very funny man live, just walked on stage and the place fell apart. As is his legend, of course.
There were others, we also had Morecambe and Wise live too, (believe it or not..) On seeing their show, I believe there were few or no ad libs, it all seem to be exactly the same every night, even the stuff that seemed off the cuff (as I recall it, it was a long, long time ago..) Again, like Tommy C they came on stage and the place came alive because of them. Wow.
I recall some of the comperes too, including Marti Caine and Bobby Knutt, who were very friendly Northerners both on and off stage. Always chatted with the staff, of course neither had 'made it' very big at that time, but they both went on to 'bigger things'. Mount Everest, that's a bigger thing. And Errol Flynn he had...
Later on (1978) I actually played on the same stage with our own band.. Big night for us, Grace Kennedy (who?) was top of the bill. I signed autographs on the backs of beer mats that night, only to find them on the floor of the multi-storey car park when we loaded up our van after the gig.. that's stardom for you, all performers experience that, even Elvis ..who nearly played Sheffield Fiesta too (see article below) ..now if you believe THAT, well, I guess you'll believe anything! 
I.E. that's Elvis Presley (not Elvis Castella, Costello or any other Elvis's!)
https://www.thestar.co.uk/whats-on/out-and-about/the-fiesta-s-star-burned-bright-1-4961697
This is a pic of our band playing there, if I can load it [couldn't load it here so put it as my avatar], I am the one on bass on the right, just look at those flairs, I think we were playing 'Night Fever' when the pic was taken, or was it 'You're the one that I want' ... it might have been 'All my loving' ...memory fades... just as well, really... Pass the Horlicks...
There was PLENTY of that at the Fiesta too! 