Robert Irwin 'nervous' about walking sister Bindi down the aisle

Robert Irwin is "nervous" about walking his sister Bindi Irwin down the aisle at her upcoming wedding.

The 16-year-old wildlife photographer will be walking his 21-year-old sister down the aisle when she ties the knot with her fiancé Chandler Powell, as he is taking on the role traditionally performed by the father of the bride following the death of their dad Steve Irwin in 2006.

And now, Robert has said there's "a lot of pressure" behind the important role.

Speaking to his sister in a joint interview with Access Hollywood, he said: "It was just so sweet of you to think of me to do that ... I'm nervous, I'm not going to lie. There's a lot of pressure!"

He then added: "But I love Bindi and Chandler so much and together I know they'll achieve so much."

During the interview, Bindi confirmed she and her fiancé are planning to tie the knot later this year at Australia Zoo, which is owned by her family.

Meanwhile, Bindi previously said her engagement was "bittersweet", as although she's excited to get married, she "wishes" her late father Steve - who tragically passed away in 2006 after he was pierced in the heart by a stingray barb whilst filming a documentary - was alive to witness her big day.

She said: "It's been really challenging. It's kind of one of the happiest times in my life, but also one of the most challenging. It was genuinely a bittersweet time. In the moment it was so incredibly special, but then at the same time, for me on a personal note, there's ... there's people who I really wish could be here today for this time in my life. Particularly dad. I wish that he could be here to be getting excited and welcoming Chandler to the family."

Bindi knows Steve "would have loved" Chandler.

She added: "Dad would have loved Chandler so much. He would've been so excited that he's now part of our family."