Friends in high places

Kirsten Dunst and Maggie Gyllenhaal
How they met: On the set of Mona Lisa Smile, starring Julia Roberts, in which the two hit it off on-set.

What they do together: Maggie introduced her brother Jake to his on-off girlfriend Kirsten, and the pair often spend time with Maggie and her partner Peter Sarsgaard. They enjoy a low-key life away from the spotlight, and often share meals and walks together in New York.

Why their friendship works: Both are level-headed and fun-loving. With a baby on the way for Maggie and Peter, Kirsten reportedly can't wait to be a godmother for her pal's little one - and Uncle Jake has such a sexy ring to it!

Gwyneth Paltrow and Madonna
How they met: The duo united over their love of Pilates and yoga, as well as art, healthy living and music.

What they do together: They are often spotted in the front row at fashion shows, and also go to fitness classes together. Gwyneth was maid of honour at Madge's wedding in Scotland.

Why their friendship works: Madonna was Gwyn's rock after the death of her father, Bruce Paltrow, and has also helped her when she became a mum for the first time to Apple. 'She has been someone to lean on. She always has the answer,' says Gwynnie, who is very protective of her high-powered pal. 'I love Madonna. She is really driven - she was actually doing Pilates with broken bones.'

Nicole Richie and Lindsay Lohan
How they met: The super-slim twosome share a love of parties and fashion.

What they do together: Go clubbing! They are regularly seen together at nightspots in LA, New York and Miami.

Why their friendship works: The girls have both faced criticism for their tiny frames and hard-partying ways. They share the same celebrity stylist, Rachel Zoe, and often share style tips. Both are also musical, and Lindsay may have been giving her skinny pal advice before Nic releases her album.

Ben Affleck and Matt Damon
Their lifelong friendship began when they were kids in Boston, then they penned Good Will Hunting that won them an Oscar for the screenplay. Sharing their dreams of becoming big film stars when they were young has kept Ben and Matt inseparable.

George Clooney and Brad Pitt
Ocean's Eleven cemented the friendship between this dreamy pair. They enjoyed plenty of high jinks on set, including lots of practical jokes - with Brad telling crew members to address George only as 'Mr Ocean'.

Leonardo DiCaprio and Tobey Maguire
They met on the audition circuit as kids, and have been friends ever since, partying and spending summers together. They are both successful actors these days and can often be spotted ringside at basketball games.

Heath Ledger and Jake Gyllenhaal
After their intense experiences on the set of Brokeback Mountain, Heath and Jake have become firm friends. They share more than just matching chiselled cheekbones - Jake is godfather to Heath's baby with Michelle Williams, nine-month-old Matilda.

Tom Cruise and Jamie Foxx
They starred together in Collateral and are now great friends - Jamie even gate-crashed a live interview with Tom in the UK recently to present him with a basket of goodies for new baby Suri. Tom says he wants Jamie, and fellow buddy Kanye West, to be 'uncles' to his daughter.