Sir Andy Murray and his wife Kim are celebrating the birth of their first son.

Kim, 31, sparked pregnancy rumours in July after arriving at Wimbledon wearing a maternity top while cheering on her husband in a mixed doubles match with Serena Williams.

Now it has been reported that the couple have broken the news of their third child to loved ones.

Andy Murray's grandfather Roy Erskine, told The Scottish Sun: “It’s a wee boy, I don’t know his name yet. I’ve seen photos. I’m just glad it’s over. They’re doing fine.”

READ MORE: McDonald's boss fired over relationship with employee

The two-time Wimbledon champion said last month he may need to rearrange his playing schedule depending on the timing of the new arrival.

Sir Andy and Kim are already parents to daughters Sophia, three, and Edie, who will turn two next month.

The couple got married in Sir Andy's home town of Dunblane in 2015.

The birth comes as he continues his comeback from major hip surgery. 

READ MORE: Andy Murray wins European Open title 

Following his win at the European Open in Antwerp last month, he joked that he needed to get back on the road because his ever-expanding family was getting "out of control".