Was that dress blue or gold? How about that old Vans shoe鈥 turquoise and grey or pink and white?

And now, the latest great debate of our time鈥

Are tennis balls green or yellow?

This time, however, it鈥檚 Roger Federer鈥檚 fault.

During a visit to Chicago to prepare for September鈥檚 Laver Cup, the world鈥檚 top-ranked tennis player was asked the divisive question by a fan.

In a video captured by the fan鈥檚 daughter, the man can be heard shouting 鈥淗ey Roger! Are tennis balls green or yellow?鈥

The tennis great flashes a big grin before responding with 鈥淭hey鈥檙e yellow, right?鈥

Little did he know that simple answer would incite a firestorm of debate online.

by Delaney Dold, the woman who shot the video, where it has since been viewed more than 315,000 times. In the comments below, Twitter users pronounced their allegiance to team green or team yellow.

There were many commenters who ruled that it didn鈥檛 matter what the actual colour of the balls are now that Federer had weighed in on the matter.

Other users provided more specifics for their choice of colour.

Finally, there were some who just couldn鈥檛 decide.