'Happy 40th Rob!!': Man behind infamous billboard was trying to keep his birthday 'on the down low'

The giant billboard is located on the side of The Wiltshire on Victoria Apartments on the corner of Victoria St West and Hobson St. Photo / Supplied

Robert Harvey was trying to keep his 40th birthday "on the down low" and hoping it would just slide by.

But that was completely upheaved this morning when his face was plastered on a giant billboard in central Auckland.

The CEO of Dentsu Aegis Network NZ wasn't aware that he had become infamous until a friend sent him a link to a Herald article.

The article detailed how a large photo and birthday message had appeared on a giant QMS billboard, located on the side of The Wiltshire on Victoria Apartments on the corner of Victoria St West and Hobson St.

It features a photo of Harvey and the words "Happy 40th Rob!!".

Harvey said when he saw the article he thought it had been Photoshopped, before realising his colleagues had "stitched him up".

"It is just hilarious," he said. "I knew my team were responsible immediately."

Harvey's colleague said the billboard, which will be up for the entirety of the day, was just one in a line of pranks the office had in store for his birthday.

"He knew nothing about it until he had a call this morning on his way to work," Sharee Campbell said.

"We have surprised him with a drag queen visit, a balloon-filled office, a giant billboard and no doubt there will be more shenanigans throughout the day.

"That's what happens when you turn 40 and have 175 staff that adore you."

Harvey said the billboard was pretty unmissable and "just goes to show the power of outdoor media".

"I'm very grateful for all the birthday love … I just wish they could have chosen a more flattering picture," he said.

"I am kind of just waiting to see what happens next to be honest, but I take that stuff pretty well."

After the day's antics, Harvey said he was looking forward to a quiet dinner with friends and family, but "not a big party or anything".