Ilie Nastase has been involved in a racism row after being heard making a derogatory comment about Serena Williams' unborn child.

Williams revealed earlier this week that she is 20 weeks pregnant with fiance Alexis Ohanian and will miss the rest of the tennis season as a result.

During the Fed Cup draw in Constanta on Friday (21 April), Nastase made the comment when fellow Romanian Simona Halep was answering questions about the world number two's pregnancy.

"Let's see what colour it has. Chocolate with milk?" the 70-year-old said in Romanian to his team members.

The Romanian Tennis Federation has declined to comment as of now with president George Cosac not having stayed for the conference, however, a spokesman for the International Tennis Federation (ITF) is aware of the comments and claim to have begun their investigation.

"The ITF does not tolerate discriminatory and offensive language and behaviour of any kind," the statement read, as quoted on BBC. "We are aware of alleged comments made by Romanian captain Ilie Nastase and have begun an immediate investigation so that we have the full facts of the situation before taking further and appropriate action."

It is not the first time that Nastase — who was appointed captain of the Romania team in October and is notably a former president of Romania's tennis federation — has made comments on the Australian Open champion either.

In late March, the former world number one made unsubstantiated claims that Williams was doping based on her physique in an interview with Romanian media.