Ronaldo, LeBron James & the highest paid athletes in the world

Detroit Lions quarterback Matthew Stafford signed a five-year deal worth $135 million (£102.5m) in 2017 and he has now entered the top 10 of Forbes' list of the world's highest-paid athletes as a result.

As well as his lucrative salary, Stafford is rewarded in the form of signing and performance bonuses, as well as earning money through endorsements with Nike and PepsiCo.

Matt Ryan signed a new deal with the Detroit Falcons in May 2017 worth a total of $150m (£114m), or $30m (£22.8m) a year.

The 33-year-old also earns around $5m (£3.8m) from endorsement deals with a host of companies, including Nike, IBM, Gatorade and the automobile manufacturer Mercedes-Benz.

Golden State Warriors made Stephen Curry the NBA's first ever $200m (£152m) player by handing him a fresh contract last summer.

However, Curry's off-field earnings through endorsements with the likes of Under Armour, Nissan/Infiniti, Chase and Vivo, far surpass his basketball salary.

One of the greatest tennis players of all time, Roger Federer remains one of the biggest earners in sport, despite the fact that he has entered the final stages of his career.

The 36-year-old Swiss recently brought his tally of Grand Slam titles to a record 20 by beating Maran Cilic in the finals of both Wimbledon and the Australian Open over the 12 months, but the bulk of his earnings come via sponsorship deals.

Federer's endorsements of brands such as Mercedes-Benz, Rolex and Wilson are the main reason for his position in the top 10.

He recently joined the Los Angeles Lakers and LeBron James arrives in California as the NBA's highest earner.

The former Cleveland Cavaliers star is fittingly referred to as 'King James' and he has a vast array of endorsement deals, which significantly boost his income. Among the partners James works with are Nike, Coca-Cola and Beats by Dre.

Interestingly, he also owns a two per cent stake in Premier League club Liverpool and, according to Forbes, the club's run to the Champions League final reaped dividends.

Neymar became the most expensive footballer of all time when Paris Saint-Germain paid Barcelona €222m ($258m/£196m) for his services in 2017.

The five-year deal with French giants PSG makes the Brazil international one of the best-paid footballers in the world and his salary accounts for the bulk of his earnings.

However, Neymar is also a highly marketable star, particularly in his native country, and he has a variety of sponsorship deals with the likes of Nike, Gillette, Red Bull and Beats by Dre.

Mixed martial artist Conor McGregor made history in the Ultimate Fighting Championship as the promotion's first ever two-weight world champion, but his status as one of the richest athletes in the world has come about outside of the octagon.

The Irishman's outrageous cross-over fight with boxing icon Floyd Mayweather made him one of the best earners in sport and he pocketed an estimated $85m (£64.5m) from that bout, despite losing.

The earnings from that lucrative showdown in Las Vegas are supplemented by McGregor's various sponsorship deals. His partners include Burger King, Monster Energy, Beats by Dre and HiSmile.

As well as all that, the Dublin native has a residency deal with Wynn Las Vegas, which hosts his fight after-parties, and he has also invested his money into a variety of digital industries.

Cristiano Ronaldo added a fifth Champions League title and a Ballon d'Or to his list of achievements during the course of the past season and he has long been one of the best-paid athletes in the world.

Ronaldo signed his last deal with Real Madrid, which made him the club's best earner, in 2016, but he has since moved to Serie A giants Juventus in a €100 million (£88m/$117m) transfer. He is reported to be earning around €30m (£26.5m/$35m) a year with Juve, which is believed to be a reduction on his previous terms.

In addition to his colossal earnings from football, the Portuguese icon is the most recognisable face in football and his endorsement portfolio is extensive. 

Ronaldo is reported to have a lifetime deal with Nike and has also become the chief attraction used by EA Sports to sell their FIFA video game series. Other partners include Herbalife, Egyptian Steel and American Tourister.

Of course, Ronaldo has also released his own fashion range and has opened a number of hotels and gyms around the world, ventures which boost his income.

Lionel Messi helped Barcelona to the Liga title in 2017-18 and finished the season as the top scorer across Europe's top leagues, winning the Golden Shoe.

The Argentina captain put pen to paper on a new contract with the Catalan club in 2017, making him the highest paid footballer in the world, with a mammoth €700m ($814m/£620m) buy-out clause.

Off the pitch, while he does not come close to his long-time rival Cristiano Ronaldo, Messi is still a lucrative earner, being the chief draw for the sports manufacturers Adidas. As well as that, he endorses the products of Gatorade, Pepsi and Mastercard, among others.

Boxing sensation Floyd Mayweather has reached the end of his fighting career, but the 41-year-old finds himself at the top of Forbes' list of the world's highest-paid athletes for the fourth time in seven years after a money-spinning bout with MMA star Conor McGregor.

That event, which Mayweather won, saw him pocket around $275m (£210m) and he added a further $10m (£7m) through sponsorships, with Hublot, in particular, being a prominent partner.