Jaden Smith, 15, helped his girlfriend Kylie Jenner, 16, clasp a gold necklace around her neck during a day out in West Hollywood on Tuesday, Nov. 19; the couple also went on a "romantic lunch" date Credit: FAMEFLYNET PICTURES

Anything for his girl! Jaden Smith and Kylie Jenner aren't shy about showing their affection toward one other -- and the Karate Kid actor has the bling to prove it! During a day out together in West Hollywood on Tuesday, Nov. 19, Smith treated the Keeping Up With the Kardashians star to a special gold necklace.

In new photos, Smith, 15, is seen standing behind Jenner, 16, while trying to clasp a gold necklace around her neck in an upscale crystal shop. Will and Jada Pinkett Smith's son is seen wearing an oversized jacket as Jenner is smiling big, donning a white crop top, floral pants and sunglasses placed on top of her head.

But that's not all! The couple spent most of the day together, and were also spotted at Urth Caffe on Melrose Ave. having a "romantic lunch," a source told Us Weekly. The two didn't mind about privacy, and instead sat right outside in front as they enjoyed their meal.

Us exclusively reported in March that the stars' friendship turned romantic. "It's new, but they've been friends forever," a source told Us at the time.

Indeed, Jenner even opened up about their budding relationship back in July in a heartfelt letter to Smith on his 15th birthday. "Although we can't remember exactly when we met, I couldn't be more grateful that we did," she wrote via social media. "You understand me like not many do and you always know the right time to make me laugh. And no, you haven't failed once to catch me when I attempt to walk or open the door on my every entrance. Happy birthday to my best friend."

Three months later, the reality star retweeted a sweet message on the same night she attended the Hollywood premiere of Ender's Game with Smith on Oct. 28. "I hope you fall in love with someone who makes you question why you ever thought you would be better off alone."