Steve Martin and Martin Short Honor Catherine O'Hara During Comedy Show

Steve Martin and Martin Short raised a glass to Catherine O'Hara during their comedy show Friday night, just hours after TMZ broke the news of her death.

Check out the sweet tribute -- they had an image of the late actress on a screen during their 'Best of' tour stop in Austin, Texas, as Martin doted over her as "the greatest, most brilliant, kindest, sweetest angel" they had ever worked with.

They raised their glasses and clinked them in her honor as the audience erupted in cheer.

As we told you, Catherine died Friday after being rushed to the hospital in serious condition. She was reported by dispatch personnel as having trouble breathing. A cause of death hasn't been revealed ... though in the past, she said she had cardiac inversus, or dextrocardia with situs inversus.

The rare condition occurs when someone's heart and other organs are on the opposite side of the body compared to most people. People can go their whole lives without ever knowing they have the condition ... however, in rare cases, it can cause complications -- especially with the heart.