Kylie Jenner, 16, acts her age for a change as she tucks into burgers and milkshakes with Kendall and Jaden Smith

With years in the spotlight under the belts already, and their modelling careers blooming, it’s easy to forget that Kendall and Kylie Jenner are still teenagers.

But the precocious reality stars acted their age for a change on Sunday as they enjoyed a low-key afternoon.

The dynamic duo treated themselves to burgers and shakes at fast food joint Fatburger in Los Angeles.

Just like any other teenagers: Kylie (pictured) and Kendall Jenner enjoyed a lazy Sunday afternoon at Fatburger in Los Angeles with Jaden Smith (L) and other pals

They were joined by a group of friends, including Will Smith’s son Jaden, who is believed to be Kylie’s boyfriend.

Kylie, 16, and Jaden, 15, took charge of placing the orders and headed to the counter while Kendall relaxed at a table with the rest of their pals.

Kylie, who is the youngest member of the Kardashian clan, looked stylish in a white blouse tucked into a black spotted skirt.

Treating themselves: The precocious reality stars were seen digging into burgers and milkshakes at the table

Daytime date?: Jaden and Kylie, who took charge of placing the orders, are believed to be boyfriend and girlfriend

She also wore a black leather jacket slung over her shoulders and had a pair of round sunglasses tucked onto her top.

Kendall, who will turn 18 in a fortnight, was sporting a black tank top and khaki trousers, and had her oversized shades atop her dark brunette locks.

The girls appeared to be having a great time but Jaden was, as always, showing off a pouty expression.

Design duo: The sister act were plugging their holiday collection for PacSun as Kendall posted this photo from the ad campaign to her Instagram page on Monday

Going their separate ways: After the meal, Kendall and a male friend did some shopping at Amoeba Music

The After Earth star was wearing an unusual red cropped hoodie with the words ‘Bear River Casino’ written on it, over a black T-shirt and skinny jeans.

Earlier in the day Kylie was seen hitting the mall while dressed in a white tank top, Daisy Dukes and cowboy boots.

And after their meal Kendall and Kylie went their separate ways, with the elder sister shopping at Amoeba Music store in Hollywood with a male friend.

One day, two looks: Earlier on Kylie was seen shopping in a tank top, Daisy Dukes and cowboy boots

Girl talk: The youngest member of the Kardashian clan was spotted hitting the mall with a friend

It seems like the close knit sisters had a great weekend, as on Saturday they cheered on their brother Brandon and his wife Leah who were performing a concert at the Troubadour.

Fortunately it was an all-ages event, as the pair are currently facing allegations that they presented fake IDs at 21-and-over nightclub Vignette on Tuesday, which was featuring the sex-themed Wax Rabbit night.

According to TMZ, their mother Kris has said they didn't have doctored identification while the manager of the club is saying they did.

Officials are 'aggressively determined to expose the truth,' according to the report, and have asked for surveillance video.

Fun weekend: On Saturday night Kendall and Kylie watched their brother Brandon and his wife Leah perform with their band in concert at the Troubadour