Miley Cyrus isn’t the first pop star to get Robin Thicke into trouble. A source reveals exclusively to In Touch that 10 years ago, Robin was secretly spending time with another controversial singer: Britney Spears!

The pair had a fling in 2003 — when Britney was at the top of her game and Robin was trying to get recognized. “He was trying hard to develop a reputation as a hot, young singer, and Britney was the biggest thing in show business,” the source tells In Touch, sharing that the two met collaborating on a project (which was never released) and “started hooking up.”

Robin’s reps deny any such relationship. However, the source says that while the “Toxic” singer was newly single, recently splitting from Justin Timberlake, Robin had been dating actress and now wife Paula Patton since high school— a fact he was keeping quiet then.

But it wasn’t meant to be between Britney and Robin. In January 2004, Brit wed pal Jason Alexander in Las Vegas for 55 hours, while Robin, 36, married Paula a year later.

For more, pick up the latest issue of In Touch, on newsstands now.

Check out In Touch’s contributing senior news editor Noah Levy discuss this story and more on VH1’s The Gossip Table! You can get more scoop from In Touch by tuning into The Gossip Table weekdays at 9:30 AM EST on VH1! 

Have a tip? Send it to us! Email In Touch at contact@intouchweekly.com.