Bruce Willis's 50th birthday is next week and his hairline is not so much receding as extinct.

But he's still a teenager at heart. His latest squeeze is said to be 18-year-old actress and singer Lindsay Lohan, star of hit films including Freaky Friday and, when she was 11, The Parent Trap.

Willis is five years older than Lindsay's father and she is only two years older than his eldest daughter Rumer.

The two found plenty to talk about, however at a party in Beverly Hills following the premiere of his latest film Hostage.

They spent the evening flirting and giggling in the bar of the Peninsula Hotel before retiring to a private suite with a few friends.

A fellow partygoer said: 'They couldn't keep their hands off one another.'

At one point Willis, best known for the Die Hard series of movies, pulled down Lindsay's trousers to reveal a tattoo saying La Bella Vista (the beautiful view) on her right buttock.

Although Willis would be her most senior boyfriend, Lindsay is known to be attracted by older men. She was linked recently with 34-year-old MTV star Johnny Knoxville.

Not that she needs a sugar daddy - for her latest film, Lucky, she earned £5million.

No one, of course, would ever suggest that by cavorting with a girl 31 years his junior Willis is trying to outdo ex-wife Demi Moore.

Since they parted in 1998, 42-yearold Miss Moore has spent £200,000 on plastic surgery and is rumoured to be contemplating marriage to her lover, actor Ashton Kutcher, 27.

As well as Rumer, Miss Moore has two other daughters by Willis - Scout, 13, and ten-year-old Tallulah.