McLellan was born in Middlesbrough, where her father was an engineer with ICI, but her family moved to Dumfries when she was 12 years old.[2] McLellan had two older sisters.[3]
McLellan trained at the Glasgow School of Art.[4]
In 1987, she also attended Cincinnati University on a scholarship. Later, she attended the Cite Internationale de arts studios in Paris, France.[2] She exhibited at the National Portrait Exhibition at the Royal Scottish Academy.[2]
In 1998, McLellan began to show signs of health issues while in Japan.[1] She was later diagnosed with multiple sclerosis.[1] Despite the diagnosis, McLellan insisted on living her life in a similar manner to before she became ill: she walked up four flights of stairs to her studio for as long as she was able.[1] When she could no longer stand, she worked in her studio from a wheelchair.[1]
She was known for still-life paintings consisting of "pared-down, almost abstracted, images of single plants, flowers, and other distinct items, set against richly-worked backgrounds of saturated colour"[3] and portraits, both bearing the strong influence of Japanese art.[4] Scottish art traditions were also an important influence on her work.[5] The process of creating her art involved a "detailed process" of building up multiple layers of acrylic paint on canvas.[1]
McLellan was considered a hard worker, and had been in her studio working the day that she had to be taken into hospital for the last time. She died there a week later.[1]
McLellan met her partner, painter Alasdair Wallace, at the Glasgow School of Art. After being together for eighteen years,[6] they married in 2009.[3] She died aged 40 the same year from complications of multiple sclerosis.
