The boss of the Hollywood sign has claimed that CGI was used in a video showing Sydney Sweeney decorating the landmark with bras.

The Euphoria star went viral last week after a clip of her hanging underwear on the tourist attraction was recorded without permission and Jeff Zarrinnam, the head of the Hollywood Sign Trust, is convinced that parts of the footage were digitally altered.

Sydney, 28, uploaded the clip to her Instagram account and Zarrinnam is convinced that the video's concluding shot - showing the actress posing and celebrating with the bra-covered sign behind her - has been altered with CGI as climbing the 50-foot sign at night would be a very delicate job.

He told the BBC's Newsbeat: "They used CGI for that.

"There's no way you could have covered the sign in that amount of time.

"It would take you hours to do that."

Zarrinnam also stated that it has been incorrectly claimed that Sydney can be seen climbing the letter H in the video.

He said: "I know that sign intimately.

"She was climbing the letter L.

"If she'd tried climbing the H she probably would've fallen and broken her neck."

It has been suggested that the Christy star could face criminal charges for the stunt - which promoted her new lingerie brand Syrn - and Zarrinnam is conducting an investigation into what happened, although he has not yet received a reply from Sydney or her production company.

He said: "I have to be fair.

"Sydney Sweeney probably isn't reading paperwork.

"Did she think she had the right to do that? Did her production team tell her what the do's and don'ts were?"

Zarrinnam says that the decision to press charges against Sydney is down to him and is something that he is seriously considering once he gets a full picture of what happened.

He explained: "I'm upset and the neighbours are upset about it.

"We have to get the word out so people don't think they can get away with it."

Zarrinnam also revealed that he is planning to increase security around the sign following the publicity stunt.

He said: "You'll even see on the video there are no trespassing signs around the perimeter of the fence.

"Looks like I might have to buy some more."