Heidi Klum has insisted she was treated "with the utmost respect" while working on America's Got Talent, as controversy surrounds the show following Gabrielle Union's exit.

Union and Julianne Hough were drafted in to replace the model and Spice Girls star Mel B on the judging panel of the show and were subsequently fired after one season on the programme back in November, with reports suggesting the Bring It On star raised a number of race and sex-related matters behind the scenes that were not reported to TV officials.

Klum, who has returned to the show for the new America's Got Talent: The Champions series, defended the programme during the Television Critics Association's winter press tour.

"I've only had an amazing experience," the 46-year-old said, reported E! News. "I can't speak for (Gabrielle). I didn't experience the same thing. To me, everyone treats you with the utmost respect. I've never seen anything that was weird or hurtful."

Variety reported that Union believed she was fired because she asked network bosses at NBC to address an environment that tolerated racist jokes and remarks, including what she said were multiple notes from producers saying she was wearing her hair "too black" for the show's audience.

The accusations were followed up by a "productive" meeting between Union and the network, with an investigation by entertainers' union SAG-AFTRA currently ongoing.