Justin Theroux once made a surprise visit to a girlfriend - and found her in bed with someone else.

The 'Spy Who Dumped Me' actor - who split from wife Jennifer Aniston in February - had a ''clingy'' girlfriend when he was 17, who felt frustrated that he was busy working ahead of leaving for college, so he decided to be ''romantic'' one day and pop round unexpectedly, much to the horror of her roommate.

He recalled in an interview with 'Entertainment Tonight': ''I had a girl in high school who did that extra crazy thing where she ... like, I was going to college and she had to stay here and she was like, 'I miss you, I love you, why aren't we together' and I was like, '[I'm] going to work and trying to get ready for college.'

''It sounds very sweet, then I did the romantic thing of surprising her.

''I made the money for the summer to go to college and then I was like, I've got two weeks before I got to go, let's go see what she's up to, you know, like 'click click,' open the door.

''Her roommate was like, 'Oh my god, what're you doing here?' and then I was like, 'Shhh' and I went into her room and someone was there.

''And then I realised, her roommate wasn't doing the 'Oh my god, what're you doing here?' she was actually like, 'Oh god, what're you doing here?' I was totally misreading the situation.''

And the 46-year-old actor can still remember how furious he felt when he opened the door and saw them together.

He said: ''Like blood, blood, blood coming out of my ears.''