Grant Denyer tries to clean up rude graffiti on his posters

A dismayed Grant Denyer has vowed to find the vandal who drew phallic images over his face in a poster for his new TV show, Celebrity Name Game.

The 41-year-old television host was alerted to the graffiti issue on social media two days ago, and yesterday located the offending poster at a bus stop.

"I FOUND IT," he wrote alongside a video he shared on Instagram. "I'm going all CSI on this crime scene. It's just a matter of time I WILL find you."

In the video, Denyer can be seen approaching the bus stop and says, "Oh God. Here it is. I found it and it's a beauty. Check it out. What cheeky bastard did that? It's a ripper."

An optimistic Denyer then attempts to clean the drawing off with a dry tea towel.

In another Instagram video, the former Family Feud host realises his attempts have been futile.

"It's not coming off," he says. "All I've done is make it the cleanest dick in Sydney."

In the caption, he vowed to find the criminal one day.

"Dear Vandal, I have a very particular set of skills," he wrote. "I will look for you. I will find you and I will kill you. Grant Neeson."

Finally, attempting to see the brighter side of things, Denyer wonders if the symbol is simply a unicorn horn.

Maybe! But probably not.