May 30, 2013 - 10:03 BST hellomagazine.com Jaden Smither dressed in an Iron Man suit for lunch at Nobu with his girlfriend Kylie Jenner before attending the premiere his latest film, After Earth, with Will Smith, Alfonso Ribeiro, Willow Smith and Jada Pinkett Smith Jaden Smith dressed up for his date with girlfriend Kylie Jenner on Wednesday. The pair were joking around at one of their favourite restaurants, Nobu 57, where Jaden sported an Iron Man costume, before they headed to the premiere of Jaden's latest film, After Earth. The two have been pretty inseparable since they confirmed their relationship last month. "She's one of my best friends," Jaden said of his model love in an interview. "I was in LA, we were all hanging out. Then I went to New York and she came too, then she came here and surprised me." VIEW GALLERY Jaden SmithCLICK ON PHOTOS FOR FULL GALLERY Jaden, 14, embraced his inner superhero in the suit, complete with a full mask as he strode out of the New York eatery with Kylie, who was dressed in a more sophisticated outfit. Stylish Kylie, 15, teamed a leopard print dress with black heeled boots and a selection of glittering jewellery, including a large gold 'K' on a necklace. Jaden politely held the car door open for Kylie as they left the sushi restaurant to get ready for the evening's premiere. VIEW GALLERY Jaden Smith, Willow Smith, Will Smith, Jada Pinkett Smith and Trey Smith "#AfterEarth premiere :)" tweeted Kylie, excited to see her boyfriend's starring role in the sci-fi thriller. Kylie did not walk the green carpet with her rapper boyfriend, who stepped out with his famous family. Jaden's father Will Smith stars alongside his son in After Earth, which was produced by The Smiths' matriarch, Jada Pinkett Smith. Kim Kardashian's half-sister Kylie chose a matching black top and skirt combination for her appearance at New York's Ziegfeld Theater. VIEW GALLERY Kylie Jenner Jaden's friend Justin Bieber also attended the premiere, as did Alfonso Ribeiro, Will's Fresh Prince of Bel Air co-star. Jaden, Will and Alfonso caused a stir at the weekend by performing the '90s show's famous rap on Graham Norton's chat show. Alfonso, who played Will's cousin Carlton Banks in the show, then delighted fans by performing his famous 'Carlton dance' for the enthusiastic crowd who sang along to the Tom Jones track, It's Not Unusual.