Diana Ross Sings Her Classics at Byron Allen's Oscars Gala

Diana Ross pulled out all the stops in the name of Oscar Sunday ... giving people in attendance at Byron Allen's annual gala a night of endless love.

The former Supremes singer was havin' a blast headlining Byron's shindig at the Beverly Wilshire Hotel, busting out some of her classics from the past 6 decades.

The 78-year-old icon performed for about an hour and had 3 costume changes over that period. Yes, Miss Ross still knows how to put on a show!

Believe it or not, Diana wasn't the only big event at this shindig -- attendees could also pay money, which went to Children's Hospital L.A., to get roasted by the famed roastmaster Jeff Ross -- and Chrissy Teigen's mom Vilailuck was one of the lucky donors.

Take a look, Jeff doesn't go easy on her, but we guess that's the best bang for your buck -- no pun intended. Howie Mandel MC'd the roast and threw in his 2 cents too.

Despite Jeff's harsh roasting of several folks who donated to the cause, not a single comedian was slapped!!!