If im flying out on the a380 with Singapore Airlines which still has the small economy at the back, Would it be possible to ask my friend to come up to business class during the fl

If im flying out on the a380 with Singapore Airlines which still has the small economy at the back, Would it be possible to ask my friend to come up to business class during the flight if I may wish?

Emirates Did not allow me to, I could go down but the friend could not come up so I assume they Singapore Airlinss won't allow it either (I tried to look at first when I flew Singapore J on the A380 which they would not allow me)

I don't think so as the airline probably won't want people from Economy to use the Business toilets making their Premium Business Passenger wait and as it could also disturb them.

No chance, quite a cheeky request too just quietly

You can visit your friend, however your friend chose economy so they stay in economy. 

In BA I was flying First (complimentary upgrade from them) while my wife was in business. They never object for her came over, though reject diner for two of us. Ask politely.