Home and Away star Johnny Ruffo has revealed he's undergoing chemotherapy after being diagnosed with cancer again.The 32 year old, who is best known for playing Chris Harrington on the popular Australian soap opera, made the announcement on his Instagram feed with several snaps shared with his 230,000 followers. In one photo, the star can be seen wearing a black patterned T-shirt with grey jeans and black boots as his hand rests on a table, connected to a drip.