Actress and Singer Hilary Duff.

Hilary Duff has been warned by police that an obsessed fan is trying to propose to her.

The 28-year-old actress was contacted by officers in Beverley Hills after they became concerned about the unnamed man's odd behaviour.

According to gossip website TMZ, the ordeal started earlier this month when he hired a limo driver and had a picture of Hilary's house but didn't know the full address.

So he got the driver to search for the property for two hours, during which he spoke endlessly about his intent to marry Hilary.

When the car journey was over, the driver was so worried that he called the police, who then contacted Hilary's team.

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Insiders claims the former Lizzie McGuire star's security team know who the man is and what he looks like as they've had issues with him in the past.

However, Hilary - who has a four-year-old son, Luca - is yet to file a police report or seek a restraining order and, instead, has just upped her security.

In 2007, an 18-year-old man was sent to prison for stalking Hilary.

Maksim Myaskovskiy was sentenced to 117 days in jail and five years probation after pleading no contest to the charges.

He was arrested Hilary and her then-boyfriend Joel Madden, sought a restraining order against him and his roommate, celebrity photographer David Joseph Klein, 50.

- Bang! Showbiz