Tennis champ Roger Federer to have another set of twins by July.

A source close to the Federers revealed this week that the 17-time Grand Slam winner may be expecting another set of twins by wife Mirka this July.

News of the pregnancy circulated in December last year, but the couple then anticipated just one child. The Federers already had twins in 2009: Myla Rose and Charlene Riva.

Twins seem to run in the Federer line. The tennis star’s older sister Diana is also mum to twins.

The Federers have yet to make an official comment on the news. But two bundles on the way may usher in more luck for the Swiss tennis ace who is currently ranked world’s number 8 in the ATP World Tour Singles Ranking.