Haye joins the contestants and fitness experts for a final week of intense weight loss training.
The boxer takes them through a boxing training programme and encourages the semi-finalists to discover a winner's mentality. Haye tries to teach the contestants how to keep going mentally even when their bodies have given up.
Speaking after the training with Haye, contestant Kevin tells the cameras: "It was like being in the same room as Rocky. It was awesome."
Alongside the challenge with Haye, the contestants will also be sent to Brecon Beacons for SAS training in mud, wind and rain. Whoever completes the course first will be guaranteed a slot in next week's grand final.
Host Davina McCall will also attempt to inspire the hopefuls ahead of the final by showing them video footage of themselves before taking part in The Biggest Loser.
The Biggest Loser airs tonight (February 28) at 9pm on ITV1.