Robert Irwin's loved-up red carpet debut with girlfriend Rorie Buckley

Robert Irwin has finally made his relationship with girlfriend Rorie Buckley red carpet official, with the pair putting on a loved-up display for photographers at the Sydney premiere of Tom Cruise's Mission: Impossible - Dead Reckoning Part One.

Robert and Rorie, who is the niece of the late Heath Ledger, looked very sweet as they posed for photos on Monday night, with the pair choosing to match in black outfits for the occasion.

The 19-year-old conservationist wore a black suit, while his 18-year-old girlfriend opted for a cut-out floor-length dress.

The pair couldn't stop giggling as they posed and cuddled up close for photographers.

Robert and Rorie were first spotted together enjoying a beach-side date in November, but neither had confirmed the relationship until now.

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It comes after Robert revealed sister Bindi Irwin is eager for him to be in a relationship so it takes the focus off her and her love life.

“It's pretty funny because of course my sister has gotten married and had a kid and there's always a lot of rumours that go around,” he told E! News.

“‘Bindi's having a second kid’ or ‘they're having triplets.’ There's always so many crazy things that happen, so Bindi always says, ‘Robert, it's your turn now. You gotta find someone to take the heat off me!’”

Robert is also reportedly close with Rorie's cousin, Matilda Ledger, with the pair reportedly bonding over having lost their fathers at such young ages.

The son of Steve Irwin was in New York earlier this year while his sister was getting surgery for her endometriosis, with Robert using the visit as a chance to catch up with Matilda.

"While Matilda hasn't spent much time in Australia, her mum [Michelle Williams] has made sure she stays in touch with her Aussie family, including her cousins on that side," an insider reveals to Woman's Day. "While Robert was in New York, there was talk of him meeting up with Matilda in Brooklyn."

"It's hard to imagine a pair of Aussie kids who share a more similar story than Matilda and Robert. It really is a twist of fate that they ended up sharing such a strong link through Rorie," another source added. "Getting to know Matilda who's in a similar boat not remembering her dad because she was so young, would be so cathartic for him."

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