Dating Musical Chairs

After ending her brief engagement to Greek shipping heir Paris Latsis, Paris Hilton took up with another Greek shipping heir, Stavros Niarchos, shortly after Niarchos broke up with Mary-Kate Olsen. Meanwhile, Avril Lavigne is engaged to Hilton's ex-boyfriend, Sum 41 singer Deryck Whibley.

Lindsay Lohan was hot and heavy with Wilmer Valderrama for several months last year. After their breakup, he was romantically linked to Ashlee Simpson. Simpson's ex-boyfriend, Ryan Cabrera, was spotted canoodling with Kimberly Stewart in October, although Cabrera insisted to the press that he and Stewart were just friends. Stewart had apparently taken up with Cabrera after dumping her fiance, 'Girls Gone Wild' mogul Joe Francis, who also used to date Hilton.

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Young Hot Hollywood

Before breaking up with Francis, Stewart was engaged to musician Cisco Adler, who is now dating and rumored to be engaged to Mischa Barton. In November, Stewart went through another quickie engagement and breakup, this time with 'Laguna Beach' star Talan Torriero. (Stewart and Torriero got engaged after two months of dating. Their engagement lasted less than two weeks.)

After Britney Spears and Justin Timberlake broke up, she was briefly linked to Jared Leto and Colin Farrell. (Notorious playboy Farrell is also rumored to have had a fling with Hilton.) Then in 2004, Spears went through a quickie marriage and annulment to childhood friend Jason Alexander, before marrying Kevin Federline all within a matter of months.

Timberlake moved on to Cameron Diaz after she ended her relationship with Leto, who has more recently been linked to Scarlett Johansson, Lindsay Lohan and Ashley Olsen. Ashley dated Leto after breaking up with nightclub impresario Scott Sartiano. After Ashley, Sartiano then moved on to briefly dating Simpson. Leto's ex-girlfriend Johansson has more recently been dating Josh Hartnett, who was romantically linked to Katie Holmes earlier this year.

And Holmes, of course, has been involved in her own high-profile whirlwind engagement to you-know-who.

Got all that?!

Not yet?

OK, here's the TMZ Guide to young Hollywood's players.

Ashlee Simpson
Age: 21
Main claim to fame: Singer/"actress"
Biggest scandal: Lip-synching fiasco on 'Saturday Night Live'
Greatest hit: 'Pieces of Me'

Wilmer Valderrama
Age: 25
Main claim to fame: Actor
Biggest scandal: Dating an underage Lindsay Lohan
Greatest hit: 'That '70s Show'

Lindsay Lohan
Age: 19
Main claim to fame: Actress /"singer"
Biggest scandal: Her father Michael Lohan's run-ins with the law
Greatest hit: 'Mean Girls'

Jared Leto
Age: 33
Main claim to fame: Actor/singer
Biggest scandal: Rumors that he cheated on then-girlfriend Cameron Diaz
Greatest hit: 'Panic Room'

Paris Hilton
Age: 24
Main claim to fame: Hotel heiress/party girl
Biggest scandal: Sex video with former boyfriend Rick Salomon
Greatest hit: Sex video with former boyfriend Rick Salomon

Stavros Niarchos
Age: 20
Main claim to fame: Greek shipping heir
Biggest scandal: Hit-and-run car accident caught on tape by TMZ
Greatest hit: Hit-and-run car accident caught on tape by TMZ

Mary-Kate Olsen
Age: 19
Main claim to fame: Actress/entertainment mogul
Biggest scandal: Sought treatment for eating disorder
Greatest hit: 'Full House'

Ashley Olsen
Age: 19
Main claim to fame: Actress/entertainment mogul
Biggest scandal: National Enquirer story (later retracted) claiming drug scandal with Scott Sartiano
Greatest hit: 'Full House'

Cisco Adler
Age: 26
Main claim to fame: Musician/boyfriend of celebutantes
Biggest scandal: Dating Mischa Barton after breaking up with her friend, Kimberly Stewart
Greatest hit: None

Mischa Barton
Age: 19
Main claim to fame: Actress
Biggest scandal: Tabloid reports of diva tantrums
Greatest hit: 'The O.C.'

Ryan Cabrera
Age: 23
Main claim to fame: Singer
Biggest scandal: On again, off-again relationship with Ashlee Simpson
Greatest hit: 'On the Way Down'

Cameron Diaz
Age: 33
Main claim to fame: Actress
Biggest scandal: Pre-fame nude photos and bondage movie
Greatest hit: 'There's Something About Mary'

Colin Farrell
Age: 29
Main claim to fame: Actor
Biggest scandal: Sex video with former Playboy model
Greatest hit: 'Minority Report'

Joe Francis
Age: 31
Main claim to fame: 'Girls Gone Wild' mogul
Biggest scandal: Arrest in 2003 for racketeering and drug charges
Greatest hit: 'Girls Gone Wild' series

Katie Holmes
Age: 26
Main claim to fame: Actress
Biggest scandal: Rumors that relationship with Tom Cruise is fake
Greatest hit: 'Batman Begins'

Scarlett Johansson
Age: 21
Main claim to fame: Actress
Biggest scandal: Diva behavior
Greatest hit: 'Lost in Translation'

Avril Lavigne
Age: 21
Main claim to fame: Singer
Biggest scandal: Tabloid reports about her alleged wild partying
Greatest hit: 'Complicated'

Britney Spears
Age: 24
Main claim to fame: Singer
Biggest scandal: Quickie wedding and annulment
Greatest hit: 'Hit Me Baby One More Time'

Kimberly Stewart
Age: 26
Main claim to fame: Being Rod Stewart's daughter
Biggest scandal: Made a public apology after calling Jennifer Aniston 'ugly' in an interview
Greatest hit: Absolutely none

Justin Timberlake
Age: 24
Main claim to fame: Singer
Biggest scandal: The Super Bowl 'wardrobe malfunction' with Janet Jackson
Greatest hit: 'Rock Your Body'