Jenna Coleman is reportedly dating Tom Hughes.
The 'Victoria' co-stars, both 30 - who play Queen Victoria and Prince Albert in the new drama - have reportedly been seeing each other for quite a few months, with the romance starting after Jenna was linked to Prince Harry last year.
A source told the Mail on Sunday: "They've been together for months, on and off since last summer.
"She chose to be with him even though Prince Harry was very keen on her.
"The reason the chemistry is so tangible is because they are dating in real life. The scenes are very real. They are completely hooked on one another."
And it has been claimed that Prince Harry unwittingly played matchmaker as his interest in Jenna made Tom ask his co-star out.
The insider explained: "Ironically Harry is largely responsible for them getting together. Jenna caught Harry's eye at the polo last year. They flirted and spent the evening together and Harry took her number and they saw each other a couple of times.
"Tom was also on the scene and made it very clear that he wasn't happy about Harry making a move on Jenna. They got together shortly afterwards."
Harry and Jenna - who previously dated 'Cinderella' star Richard Madden - were first spotted together in June 2015, when they were caught flirting at a polo party at Coworth Park, Ascot.
However, Kensington Palace denied the pair were romantically linked at the time.
A party-goer at the polo bash said: "From their body language it looked like they were really enjoying each other's company.
"Harry took her by the hand and led her away from the crowd in the sponsor's tent.
"They sat alone and talked as things were winding up inside the party. It was a very flirty, very tactile encounter. She was leaning into him and he had his hand on her knee."