Lord Marcus Beaton was a recurring guest character in Season 2 of the television series Gossip Girl.
Lord Marcus Beaton is an English Lord that Blair starts dating after she got her heart broken by Chuck . She met him inside the Yale Club and they instantly fell into each others' arms. Lord Marcus is described as a more handsome, British version of Nate Archibald. Blair saw herself marrying him and she even bought a wedding dress. Unfortunately, rumors that he's already engaged to someone else appeared on Gossip Girl's website. Blair didn't believe them at first but after being graduated, she joined Marcus in England and she quickly realized that he was showing more interest in his horse-faced cousin, Camilla. Despite that, Blair tried to make their relationship work, but Marcus didn't make enough effort. Blair then leaves England by herself, totally ignoring Lord Marcus.
Marcus is introduced as Blair Waldorf's boyfriend at the beginning of the second season. Although Blair initially dated him only to make Chuck jealous, she changed her mind once she discovered he was an English lord. Marcus seems to genuinely care for Blair, and she in turn is ecstatic at the prospect of being with royalty. Unfortunately, while he was with Blair, he was simultaneously sleeping with his step-mother, Lady Catherine Beaton, who also happened to be having an affair with Nate Archibald, Blair's ex-boyfriend.
Vanessa finds out about Marcus and Catherine's affair and shows pictures to Blair, who uses them to try and help Nate with his family's problems. Blair then breaks up with Marcus.