An honorable customer sent a heartwarming gesture to a California deli server to make sure she knew about her 'great' service.

ESPN feature writer Roberto José Andrade, of El Paso, Texas, was visiting Los Angeles on May 1 when he stopped at Langer's Delicatessen-Restaurant around 10.30am with two friends.

But when he left the restaurant, acclaimed for its pastrami sandwiches, he could not shake off the feeling that he had not left a tip.

'I'm about 75 percent sure I did,' Andrade wrote. 'Of course, that leaves a 25 percent change [sic] I didn't and honestly, that's been bothering me for the past few weeks.'

'That's why I'm sending these $50 just in case I forgot to include the tip,' he continued.

In the letter dated May 19, more than two weeks after the restaurant visit, Andrade explained that his first job was as a busboy and waiter. He added that his sister had also been a waiter for years.

'I recognize how important these tips are to workers,' Andrade said. The deli posted his letter last Friday.

Andrade specifically touted the service offered by his waitress, who he described as a 'petite Asian woman,' asking the deli to give her the $50 in the envelope 'along with my apologies.'

'As usual, the food was great,' Andrade wrote. 'I've eaten at Langer's the last two times I've visited Los Angeles; that's how much I enjoy it.'

Andrade explained that the potential tipping mishap happened as he and his friends were discussing how to break down the check.

'Since it's just easier, I pay it,' Andrade wrote in the letter. 'Still, there was some back and forth with my friends and I on who will pay what, how, etc.'

He added: 'In all that talk and math confusion, and saying our goodbyes, I drive away and somewhere stuck in traffic I ask myself, 'Did I leave a tip?''

Though Andrade acknowledged that sending the $50 in the envelope was 'probably not my smartest idea,' he surmised that it was also 'the easiest way to get this resolved.'

Langer's posted Andrade's letter on its Facebook page last week, saying that his words 'made our whole week.'

Andrade told the Daily Mail via email on Saturday night that Norm Langer, the owner of the deli, had called him about a week after he sent the letter.

He was unaware that the letter was gaining traction online until being told by a mutual friend.

'Since it had been months since the letter, I'd pretty much forgot about it,' Andrade told the Daily Mail.

Andrade said he had ordered the 'number 19,' which includes hand-cut pastrami, house-made coleslaw, Russian dressing and Swiss cheese on double-baked rye bread, according to TODAY.

'That's what they're known for,' he quipped.

He had posted about the visit to Langer's on his Instagram account when it happened, uploading a picture of the restaurant's logo and writing, 'Always hits.'

The deli praised Andrade for knowing 'exactly what that money means to the person carrying the plates,' referring to his server.

'We found her,' the deli wrote last Friday. 'She got it. And she was floored.'

The restaurant thanked Andrade for 'going out of your way to do the right thing when nobody would have known otherwise.'

'Your table's always ready here,' their post finished.

Langer, the deli owner, lavished praise on Andrade for his sweet gesture and admitted that the deli could not actually determine whether he had initially tipped.

'There's no way to tell because it was an entirely cash transaction,' he told CBS LA.

The server's coworkers described her as someone who 'does so much for this place.'

'Helping out in little places,' Frank Wurster, a server at Langer's, told the outlet. 'She's just a great person.'

The Daily Mail has reached out to Langer's for further comment.