The 23-year-old actress, who has been married to rugby league player Nate Myles since 2011, released a statement to the Australian Daily Telegraph saying that she is battling Hodgkin lymphoma.
"Tessa will be undergoing chemotherapy over the next few months," read the statement. "Tessa and Nate would like to thank all for their well wishes and would ask for privacy during this very difficult time."
Melbourne-born Tessa has returned to her native Australia from the US, where she has been working since leaving Home and Away after three years on the show.
"She has returned home to the Gold Coast to be with her husband, Gold Coast Titans Co-captain, Nate Myles," reported the Australian Daily Telegraph.
"Tessa is a much valued and loved member of the Home and Away family," a spokesperson for Seven, the network which broadcasts the soap. "She has a wonderful approach to life.
"She has always been health conscious and is full of spirit. She will tackle the next six months with great determination and we wish her all the best for a speedy recovery and send all our love."
Tessa married Nate Myles in 2011
Hodgkin lymphoma is the same type of cancer that former Neighbours star Delta Goodrem was diagnosed with at the age of 18.
The disease is a cancer of the lymphatic system which sees developing lymphocytes multiply in an uncontrolled way, collecting to form a tumour. A rare illness, Hodgkin lymphoma is most common in teenagers and young adults.