Gregg DeGuire / WireImage 1 / 23
Gregg DeGuire / WireImage 1 / 23

She's been engaged to Liam Hemsworth for just over a month and already Miley Cyrus has babies on the brain.

Set to tie the knot with the "Hunger Games'" hunk, 22, bride-to-be Cyrus, 19, isn't worried about wedding planning as much as she is family planning. "Miley and Liam really want to have a baby quickly," a Cyrus family source tells Us Weekly of the couple, together since meeting on "The Last Song" set in 2009.

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Hemsworth is said to have a strong motivating factor in the singer's pregnancy plan, given the fact that his older brother, Chris Hemsworth, welcomed daughter India in May.

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When the time comes for Cyrus and Hemsworth to expand their family -- which currently includes five dogs -- they'll already have the approval of their loved ones.

"They are both mature and ready for this," says a source of the couple, often criticized for their decision to wed so young. "Miley is 19 going on 40."

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