Things are seriously heating up on the set of Nine's new reality weight loss program Excess Baggage, with Kevin Federline, ex-husband of Britney Spears, collapsing during a filmed challenge this afternoon.

The former dancer collapsed at 2pm (EST) with chest pains after completing a challenge with the AFL's new Greater Western Sydney team.

On set medics gave him oxygen, but then decided to call an ambulance, which took him to Mount Druitt Hospital due to a suspected cardiac arrest.

An ECG test revealed Federline had not had a heart attack, but was kept in the hospital for further testing.

It is the second time Federline has had treatment during the nine weeks he has been filming the series, which kicks off next Monday at 7pm on Nine/WIN, where he weighed in at 105.4kg.

He was earlier treated for heat stress during filming in Western Australia at Nickol Bay Hospital.

Federline has teamed up on the show with a Perth contestant, Atwell's Renae Pratt.

According to a Nine spokesperson, the pair are still set to complete media commitments in Perth next Tuesday.