Jay Leno and his wife Mavis Leno made a rare public appearance ... was all smiles as he and his wife of over four decades, 77, posed for photos on the carpet and couldn't keep their hands off ...

For Jay Leno, laughter has been the best medicine in coping with wife Mavis’ ongoing battle with dementia. “I still make her laugh every day, and that’s always fun,” Leno, 74, told The Post.