John Henson, son of Muppets co-creators Jim and Jane Henson, and a board member of The Jim Henson Company, died of a sudden massive heart attack on February 14, the company announced on its Facebook page. He was 48.

Henson served as a shareholder and board member of The Jim Henson Company. He occasionally performed as the Muppet Sweetums, a toweringly large, hairy Muppet in the puppeteer troupe, in various titles including The Muppets’ Wizard of Oz, It’s a Very Merry Muppet Christmas Movie, and Muppet Treasure Island.

He is survived by his two daughters, Katrina and Sydney, and his wife Gyongyi.