Leighton Meester and Adam Brody are expecting their first child together

According to the website Popsugar.com, the brunette beauty and 'The O.C.' actor were enjoying a lunch date in Los Angeles when her bump could be clearly seen through her tight fitting T-shirt.

The couple tied the knot in a secret ceremony in January 2014 after first meeting on the set of their 2011 film 'The Oranges'.

A source said at the time: "Leighton and Adam got married in Northern California by the ocean a couple of weeks ago. It was a very small and intimate wedding with close family and friends. It was beautiful."

The 29-year-old star first hinted she and her 35-year-old beau were trying for a baby during a recent magazine interview.

She said: "Most people I know are starting to get married. It'll be kids next. I like the grown-up stuff. I like having a house. I've got dogs.

"I started [Gossip Girl] when I was so young. And once it was over, I wanted to do things that were exciting and challenging and more me - more my adult taste."

Meanwhile, Adam previously joked he is hoping to have a very big family with Leighton.

Asked how many children they were planning on having, he said: "I say twelve. And I decide."