She began as a minor character in The Muppet Show TV series, but gradually developed into one of the central characters of the show.
She is a pig who is absolutely convinced she is destined for stardom and nothing is going to stand her way. Her public face tries to be the soul of feminine charm, but can instantly fly into a violent rage whenever she thinks she's insulted or thwarted. Kermit the Frog has learned this all too well since he is the usual target for her Karate Chops. When she isn't sending him flying through the air, she is often smothering him in (unwanted) kisses.
Eventually in the films, Kermit started returning her affections and (unwittingly) married her in ''The Muppets Take Manhattan'\' - although subsequent events suggest that it was only their characters in the movie that married, and that their relationship is really the same as ever.
It is said that Jim Henson based the character on the American actress Loretta Swit.