Defending champs Muguruza, Federer descend on Wimbledon

After clay turned to grass with a few thrilling weeks of events on trimmed lawns, the top stars of the game have started hitting the courts at the All England Club. A slew of past champions are being spotted across the grounds.

Returning to Wimbledon for the first time since 2016, seven-time champion Serena Williams headed to practice.

Fresh off his historic 11th French Open triumph in Paris, Rafael Nadal is busy on the turf at Aorangi Park in SW19.

The Spaniard, who won the crown in 2008 and 2010, is looking to go deep at the third Slam of the season for the first time since making the final in 2011.

Defending champion Garbine Muguruza is back at the historic site, supporting her Spanish World Cup team all the way from England.

Men's defending champion Roger Federer also made his 2018 debut in the place that's meant the most to him during his storied career.

After withdrawing from Birmingham with an injury, 2004 Wimbledon winner Maria Sharapova is looking ready for action.

Sharapova will be making her first appearance in London since 2015, when she lost in the semifinals to Williams.

With some momentum from his run to the Queen's Club final, three-time champion Novak Djokovic is back to business.

A few other Wimbledon threats were also spotted on the grounds, including Juan Martin del Potro:

Grigor Dimitrov:

And Fabio Fognini:

Wimbledon qualifying is already underway in Roehampton, with main draw play beginning on Monday.