The image was captioned “hello”, along with a sun emoji.
Roberts is married to cameraman Danny Moder and the couple share three children, twins Phinnaeus and Hazel, and Henry.
Since having children, Roberts has scaled back the number of films she makes and spends much of her time on the family ranch in New Mexico.
In an interview last year, she said: “It is easy to say no (to films). And it just sort of falls into one a year, but it’s not a mathematical equation that I’m trying to stick to but fortunately I have found things here and there that hold my heart enough to want to participate in them, so that is my good fortune.”
Julia Roberts makes Instagram debut with message to fans