Kaley Cuoco is ''secretly worried'' about her marriage.

The 'Wedding Ringer' star has been forced to deny rumours her relationship with Ryan Sweeting is on the rocks in recent weeks but is reportedly doubting her own thoughts.

A source told US' OK! magazine: ''Kaley is really paranoid ... she doesn't let him out of her sight. She always asks Ryan who he's with and never knows what he's doing. She'd flip if he didn't answer his phone. And it drives him crazy.

''She is secretly worried she doesn't know him that well.''

Meanwhile, the 29-year-old actress previously admitted Ryan moved in the day after their first date.

She shared: ''We actually met on a blind date. I had never met him, and he had really never met me. He still tells me he had never seen the show, he didn't know who I was. He came to LA for a blind date - and he never left. We had been texting, we texted a little bit.

''Dinner was great, and then he moved in the next day. I know, it sounds so slutty, but it wasn't! It all did move quite fast on paper. But we really did know ... And I know you're all thinking, 'She's nuts!' I swear I'm not nuts. We just fell in love.''