Knightley, who shot to prominence in 2003's Bend it Like Beckham, was the only British star to make either Forbes's lists of the 10 best-paid actresses or the 10 highest earning actors.

Will Smith, 39, was paid the most of all, earning $80 million (£40 million) between June 1, 2007 and June 1, 2008 thanks to blockbusters I Am Legend, Hancock and The Pursuit of Happyness. He is also the first actor to have eight straight movies take in more than $100 million (£50 million) at the box office.

In second place was Johnny Depp, 45, Knightley's Pirates of the Caribbean co-star, who earned $72 million (£36 million), followed by Eddie Murphy and Mike Myers, who made $55 million (£27.5 million) each.

Diaz earned more than Leonardo DiCaprio ($45 million), Bruce Willis ($41 million) comedian Ben Stiller ($40 million) and Nicolas Cage ($38 million).

But overall, the 10 best-paid actors out-earned the 10 highest-earning actresses by two to one over the year, according to figures detailed in Forbes's special Entertainment All Stars issue.

A separate list of top-earning entertainment industry 'tweens' featured three British Harry Potter stars and was topped by Daniel Radcliffe, 19, who shared the number one spot with Miley Cyrus, the 15-year-old Hannah Montana star. Both earned $25 million (£12.5 million) last year.

Radcliffe's co-stars Emma Watson, 18, and Rupert Grint, 19, also made the top 10, coming in at six and eight and earning $5.5 million (£2.75 million) and $5 million (£2.5 million) respectively.

Across all of Forbes's entertainment categories, Harry Potter author JK Rowling earned the most of anyone with a total of $300 million (£150 million).

The British writer even out-earned US talk show host Oprah Winfrey, who took home $275 million (£137.5 million) last year.

c  David Beckham came second on Forbes's list of the highest-paid male athletes with $50 million (£25 million). He was beaten to the top spot by US golf star Tiger Woods, who earned $115 million (£57.5 million) last year.

Russian tennis star Maria Sharapova topped the women's list of athletes with $26 million (£13 million).

Other Britons ranked in the various lists include rock bands The Police, who earned $115 million (£57.5 million), and Genesis, who earned $31 million (£15.5 million); and Mark Burnett, the producer responsible for Survivor and The Apprentice, who earned $60 million (£30 million) last year.

Chef Gordon Ramsay and supermodel Kate Moss meanwhile earned $7.5 million (£3.75 million) each.

1. Will Smith - $80 million (£40 million)

2. Johnny Depp - $72 million (£36 million)

3= Eddie Murphy - $55 million (£27.5 million)

3= Mike Myers - $55 million (£27.5 million)

5. Leonardo DiCaprio - $45 million (£22.5 million)

6. Bruce Willis - $41 million (£20.5 million)

7. Ben Stiller - $40 million (£20 million)

8. Nicolas Cage - $38 million (£19 million)

9. Will Ferrell - $31 million (£15.5 million)

10. Adam Sandler - $30 million (£15 million)

1. Cameron Diaz - $50 million (£25 million)

2. Keira Knightley - $32 million (£16 million)

3. Jennifer Aniston - $27 million (£13.5 million)

4= Reese Witherspoon - $25 million (£12.5 million)

4= Gwyneth Paltrow - $25 million (£12.5 million)

6. Jodie Foster - $23 million (£11.5million)

7. Sarah Jessica Parker - $18 million (£9 million)

8. Meryl Streep - $16 million (£8 million)

9. Amy Adams - $14.5 million (£7.25 million)

10. Angelina Jolie - $14 million (£7 million)

1= Daniel Radcliffe, 19 - $25 million (£12.5 million)

1= Miley Cyrus, 15 - $25 million (£12.5 million)

3. Mary-Kate and Ashley Olsen, 22 - $15 million (£7.5 million)

4. Jonas Brothers, aged 15 to 20 - $12 million (£6 million)

5. Zac Efron, 20 - $5.8 million (£2.9 million)

6= Ashley Tisdale, 23 - $5.5 million (£2.75 million)

6= Emma Watson, 18 - $5.5 million (£2.75 million)

8= Hilary Duff, 20 - $5 million (£2.5 million)

8= Rupert Grint, 19 - $5 million (£2.5 million)

10. Vanessa Anne Hudgens - $3.2 million (£1.6 million)