Jeremy Renner's mystery ex-girlfriend has reportedly given birth to their first daughter.

The 'Hansel & Gretel: Witch Hunters' star welcomed his baby into the world yesterday (28.03.13), but the mother's name still remains a secret.

Us Weekly broke the news, saying they had received confirmation from two separate sources.

The former couple have been living together in Jeremy's Los Angeles home after he apparently agreed to put her up until their child was born.

An insider had said: ''They used to date but it wasn't serious. [He is] being ultra-secretive about it, but she has been going on about her life and not hiding it.''

The 42-year-old actor was previously overheard telling Eva Longoria he would be a father for the first time when the pair were spotted chatting earlier this year at the Golden Globe Awards in Los Angeles.

It was said: ''Jeremy is delighted he is becoming a dad.

''He realises it's unconventional to have his baby mama, an ex-girlfriend, living with him and his roommate, but he just doesn't care.''