Benedict Cumberbatch
Benedict Cumberbatch and fiancee Sophie Hunter reportedly expecting first childGetty

He has yet to say "I do" but it looks like Benedict Cumberbatch already has reason to celebrate.

Just months after accepting his marriage proposal, the Sherlock star's fiancée Sophie Hunter is reportedly pregnant with the couple's first child.

According to the New York Post's Page Six, the Imitation Game actor is looking forward to becoming a father and has even brought their wedding forward.

''Sophie is a few months along, and both she and Benedict are very excited about it. They are also quietly planning to marry in early spring.''

Hunter first sent the rumour mill into overdrive earlier this month when she escorted her partner to the Palm Springs International Film Festival in a flowing Just Cavalli maxidress. Onlookers suggested that her choice of outfit and cleverly-placed purse was a bid to hide changing curves.

Back in November Cumberbatch, 38, is said to have flown to Scotland to ask his future mother-in-law for her daughter's hand in marriage.

His proud parents snubbed Twitter and Facebook by announcing the wedding news in the Forthcoming Marriage section of the Times newspaper.

''I've had the most important news of my life," Cumberbatch said at the time.

''That's also sort of private, I don't want to talk about that too much. But my engagement to the woman I love is obviously the most important thing of 2014 for me.''