Robert Irwin broke down in tears as he paid tribute to his mother Terri and late dad Steve on Dancing With The Stars

During his intro package, Robert said: "She's an absolute hero to me, because I was two when I lost dad.

"As I got older, [I] started to realise just how hard it would have been for her to be there for us, and all the while continue dad's legacy that her and dad built together."

He started to cry, insisting he's "never been able to capture the feeling of gratitude I feel for it".

He added: "At every milestone when I just wished that my dad was there, she was there. And that was enough."

Terri joined Robert in the rehearsal room, and told her son that it was him and his sister Bindi, 27, who helped her cope with the heartbreak after the Crocodile Hunter legend died aged 44 in September 2006.

She said: "After we lost Steve, it was difficult to smile again. For quite a while. "So for him to say, 'You lifted me up,' honestly, it was the opposite. Because of them, I could get up every morning. Every day I'm a proud mama."

After the routine, judge Derek Hough - who was a professional on the show and danced with Bindi 10 years ago when she won Dancing With The Stars - struggled to talk through tears.

He said: "The love I have for your family. Thank you. I just have so much love for you guys.

"Man, I'm so proud of you. I really am. You've become such an amazing man and the world needs the Irwin family."

Robert told viewers and the audience that the dance was for his mother, as well as "all the mums out there who don't get the recognition they deserve".

He added: ""This is for the single parents who work so hard every day to put one foot in front of the other.

"It's for anyone who's lost, someone who feels lost-keep going. And if you can, go call your mum and tell her that you love her."