By JOHN SOUTH

TOM CRUISE and KATIE HOLMES are hiding another baby secret — less than two months after the birth of baby No. 1, they're already working on baby No. 2!

The 43-year-old "Mission: Impossible" star and his bride-to-be became parents of daughter Suri on April 18, but Katie can't wait to have another one, insiders say. In fact, they say she may already be pregnant!

"Tom and Katie are so thrilled with Suri that they want to have a second baby right away," said a source close to the couple. "And they're hoping to announce the news as early as their planned July 4th weekend wedding.

"Before Suri's birth they talked about having two or three kids — and they don't want to wait."

In fact, 27-year-old Katie never dreamed she'd take to motherhood so well.

"Katie was really scared of becoming a mom," an insider divulged. "She didn't know what to expect and she was worried that she'd be overwhelmed by all the responsibilities. But she's loving every minute of being home with Suri. Katie isn't at all concerned with getting back to work."

Pick up this week's issue of The ENQUIRER to read more about TomKat!