Chelsea Hackett (born October 29, 1999) is an Australian kickboxer, mixed martial artist and muay thai fighter competing in the Women's Flyweight division of Professional Fighters League (PFL).^[2]

Hackett was born in Melbourne and moved with her family to the Gold Coast at an early age. She attended St Andrews Lutheran College throughout her upbringing^[3] and began her martial arts journey at an after school Taekwando program at eight years old.^[4] By the age of 12, Hackett had achieved a junior black belt in Taekwando^[5] and sought out a new challenge in the form of Muay Thai under the tutelage of 10-time world champion John Wayne Parr at his Boonchu Gym on the Gold Coast.^[4] She won gold medals at the IFMA World Muaythai Championships in both 2014 and 2015 on her way to amassing a professional Muay Thai record of 16-4-3, which included two world title victories and winning the WBC World Lightweight Championship.^[6] Hackett transitioned into Mixed martial arts full-time in 2019 and adopted the nickname Ham Sandwich.

Hackett made her professional MMA debut in May 2019 for Australia's Eternal MMA promotion walked away with a majority draw that would have been a unanimous decision victory had she not been deducted a point in the first round for holding the fence.^[7] She competed for the Eternal MMA promotion three more times over the following 12 months and was victorious in every bout. Hackett was then invited to compete at Dana White's Contender Series 36 where she fought and lost to Victoria Leonardo on November 17, 2020 for an UFC contract.^[8][9][10]

Hackett signed with PFL and debuted at PFL 7 on August 4, 2023 against Ky Bennett, submitting her in the second round via rear-naked choke.^[11]

Hackett faced Jena Bishop at PFL 1 on April 4, 2024 and lost the bout by an armbar submission.^[12][13]

Hackett is set to face Dakota Ditcheva on June 13, 2024 at PFL 4.^[14]

In 2021, Hackett competed on Australian Survivor: Brains V Brawn.^[15]