Little House On The Prairie actor Richard Bull has died at the age of 89. He passed away on Monday morning (03Feb14) at the Motion Picture Television Fund community centre in California. His TV daughter Alison Arngrim broke the news to fans online on Monday night (03Feb14) by sharing a black-and-white photo of Bull on her Twitter.com page alongside the simple message, "Goodnight Pa". She added, "Today we lost my TV 'Pa', the wonderful Richard Bull. In real life, he was just as kind, intelligent, thoughtful and reasonable as you'd expect (his character) Nels Oleson to be." Fellow co-star Melissa Gilbert also took to her Twitter blog to pay tribute, writing, "This man will be missed. Goodbye Richard working with you was such a joy but not nearly as joyful as being your friend." Born in 1924, Bull began his acting career on stage in Chicago, Illinois, before establishing himself as a character actor on 1960s TV series such as The Eleventh Hour, Voyage to the Bottom of the Sea and Mannix. He will be best remembered for his role as shopkeeper Nels Oleson on Little House on the Prairie, based on the books by Laura Ingalls Wilder, who was portrayed by child star Gilbert. Bull later reunited with his Little House on the Prairie co-star Michael Landon in 1988's Highway to Heaven. He is survived by his wife of 66 years, actress Barbara Collentine.