(CNN) – Restaurants give gifts all the time, but here’s one that demands an on-going commitment to give you a gift for a year.

A California-based restaurant chain offers a one-year free hamburger to anyone who gets a permanent tattoo – also free – in the restaurant’s name.

The Farmer Boys partnered with West Hollywood tattoo parlor, The Honorable Society, and Rockin ‘Ink Tattoo, in Las Vegas, to promote the burger chain’s 40th anniversary celebration. Those wishing to participate must be over the age of 18 and fill out an online form before May 21 to make an appointment.

Fans can choose from three permanent color designs measuring 5cm by 5cm, based on the template on the restaurant’s website. All three designs bear the name of the restaurant and the hamburger.

Farmer Boys posted on Instagram that “Due to the sheer volume of requests, not everyone who submits an inquiry will have an appointment.”

For those who aren’t convinced of getting a permanent tattoo, the restaurant chain also offers free temporary tattoos on all store purchases. If you share the temporary tattoo on social media, you can win a free burger, according to one of the restaurants posted on Instagram.