Matthew McConaughey is under pressure to marry pregnant girlfriend Camila Alves - both their mothers want them to wed before they welcome their second child.

The Hollywood actor - who has a son, named Levi, with model Alves - announced on Father's Day (21Jun09) that he is to be a dad again.

In a post on his website, he wrote, "Happy Father's Day. It's my first, and the last 11 months with Levi and Camila have been the most rewarding adventure to date. We have more blessed news to celebrate this Father's Day that (will) make this time next year double the fun. Levi is going to be a big brother...

"Yeah, we pulled off the greatest miracle in the world one more time, Camila and I are expecting our second child, bringing more life into the world, making more to live for. The future looks bright as the family grows."

But McConaughey's mum Mary and Alves' Catholic mother Multo are pressing for the actor to make an honest woman out of the Brazilian beauty.

A source tells the National Enquirer, "Both mums were thrilled (with the baby news), but they wondered about wedding plans. They hoped that after little Levi was born last July that there would be a wedding. But so far, their wish has not come true.

"Camila's parents live in Brazil - and come from a culture where respectable people get married and then have babies... They don't understand why she and Matthew don't want to get married."