Bindi Irwin's wedding: Brother Robert, 16, takes on Steve's role to walk her down the aisle

Bindi Irwin and her fiance Chandler Powell. Photo / Instagram

Robert Irwin is "nervous" about walking sister Bindi down the aisle.

The 16-year-old wildlife photographer will walk his 21-year-old sister down the aisle when she marries her fiancé Chandler Powell, as he takes on the role traditionally performed by the father of the bride after 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!"

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Robert and Chandler kindly helped me choose the flowers for my bridal bouquet. They’ve been very supportive with all things wedding planning. ❤️ If you have wedding advice, please comment below. I always love and appreciate ideas. xx

A post shared by Bindi Irwin (@bindisueirwin) on Mar 10, 2020 at 12:27pm PDT

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

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

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

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Dad, Today is your birthday. I had an extra strong cup of tea just how you liked it. I hugged Mum for you and told her how much we love her. Robert and I went on a hike through the mountains you cherished. I watched one of your documentaries with Chandler and shared stories about you. I walked through your office in the zoo and smiled at our old family photographs. Today and every day I miss you and love you beyond description. You’re always with me. ❤️

A post shared by Bindi Irwin (@bindisueirwin) on Feb 22, 2020 at 4:04am PST

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."

Irwin knows Steve "would have loved" Powell.

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