Silverman is pregnant with Cowell's baby and after her divorce from ex-husband Andrew was recently finalised, the couple are said to be delighted their romance is out in the open, reported Us magazine.
"They had so much to catch up on, and there were no distractions. Plus, they love that they don't have to hide anything anymore," a source said. The pair have been enjoying having their relationship out in the open, and they were spotted earlier this month kissing in the French Riviera.
'X Factor' UK judge Louis Walsh has previously described them as two teenagers dating and thinks Silverman has been good for the TV boss. "I went out for dinner with them. I think he's going to be a great dad. She's a great influence on his life - very positive and bubbly.
"She seems to have got the fun back into his life. They are like two teenagers dating. I love Lauren. I love all his girlfriends. He is what he is," Walsh said.