The 27-year-old actress is said to have been secretly dating Christian and they have just enjoyed a romantic trip abroad, reported Daily Mirror.
"Christian is a total cheeky chappy and has no fear. He caught Lindsay's eye and just went in for the kill. He's very good-looking and Lindsay loves the British accent," a source said.
"They spent loads of time together and got pretty close, quite quickly. Neither knows whether this will lead to anything or if it was merely a holiday romance but, at the moment, Christian is really happy and quite excited.