Federer released a social media video as part of a national public campaign, telling people to follow the recommended guidelines.
"I'm also staying home, and I haven't been shaking anybody's hands for quite a lot time now," he said. "I wash my hands very frequently as we're supposed to, again and again. I believe helping each other is important more now than ever, especially because we want to help the older generation...we need to help them by keeping a distance of two meters and not shake hands.
"We need to take this very seriously."
Federer had been sidelined following knee surgery seven weeks ago, while the tours began their tournament suspension two weeks ago.
Nadal sent a video message in Spanish to health and safety workers.
"I wanted to send a message of thanks to all the doctors, nurses and all the health personnel who are all protecting us, and to the police forces, civil and national guard, the army, and all those who make us feel a little safer, who are in the first line of fire," Nadal said. "They are our heroes. I want to express my admiration and thank you all."
He also spoke of the solidarity in Spain, which has been the second-most affected country in Europe.
"There are also positive things in these difficult times. We are demonstrating to be a united people," he said.
Nadal won the title at Acapulco just before the tour suspension began.
Novak Djokovic, who had not dropped a match all season, also told his followers to listen to the guidelines.
"This is a time for us all to get together and unite. Let's really try to spend quality time with our family at home. Please stay at home in quarantine and help frontline medical people to help the people infected and in need," he said.
All tour events through the clay season have been postponed or cancelled until June 8. The tours have also announced their decision to freeze the rankings.