Penn Badgley and Blake Lively kept their breakup a secret from the Gossip Girl cast and crew - here's what we know about their former relationship

Penn Badgley and Blake Lively were one of the most talked-about couples of the noughties, dating from 2007 to 2010.

And while the former co-stars have long since married other people - Badgley to singer Domino Kirke and Lively to actor Ryan Reynolds, their past relationship has recently resurfaced.

Badgley, 38, returns to our screens this month in his infamous Joe Goldberg role for the fifth and final season of Netflix thriller, You. And as such, everything from his Gossip Girl fame to his A-list dating history is going viral.

This of course extends to his past relationship with Lively, with the Gossip Girl co-stars dating during the first three seasons of the CW show, before their high profile split.

Penn Badgley and Blake Lively

How long did Blake Lively date Penn Badgley?

Penn Badgley and Blake Lively dated on and off for three years, from 2007 to 2010. Their relationship spanned the first three seasons of Gossip Girl, where they played on-off couple, Dan Humphrey and Serena van der Woodsen.

"I remember there was one point where we were just afraid of how our personal lives overlapping our work life could be perceived by our bosses," Lively explained to Vanity Fair back in 2017. "[But then] we were like, ‘Oh no, that’s exactly what they want.’ They wanted us all to date. They wanted us all to wear the same clothes that we’re wearing on the show. They wanted that, because then it fed their whole narrative. People could buy into this world."

"We were very much caught up in the show, which itself was a six-year endurance test," Badgley has previously explained to Elle back in 2013. "I mean, like anything valuable, it was good and it was bad and it was a learning experience."

Badgley has also credited his relationship with Lively for saving him from struggling with the pitfalls of sudden fame, recalling their courtship as a positive influence.

"I never struggled with substance," Badgley recalled. "Blake didn't drink. And I think our relationship in some ways saved me from forcing myself to go down that road."

When did Blake Lively and Penn Badgley break up?

Blake Lively and Penn Badgley broke up in 2010, midway through Gossip Girl filming. But the former couple reportedly kept their separation under wraps, not wanting any "personal drama" to impact the show.

"I found out on the set of the season 2 finale that Blake and Penn had broken up months before," executive producer Joshua Safran recalled to Vanity Fair in 2017. "They kept the breakup hidden from the crew, which you could never do now.

"I don’t even know how they did it," he continued. "They kept it from everybody which is a testament to how good they are as actors. Because they did not want their personal drama to relate to the show."

"They’re professionals," a source reportedly told Us Weekly when news of the split went public. "They’re still good friends and hang out on the set."

Blake Lively Penn Badgley break up

Penn Badgley has opened up about their 2010 split previously on his podcast, Podcrushed, recalling their determination to stay professional and amicable.

"We were always very professional," Badgley explained. "I don't even think, in my memory, there was not one bit of strangeness. It wasn't even a thing.

"We were consummately professional," he has previously said on Watch What Happens Live With Andy Cohen, back in 2015. "And I think we should both pat ourselves on the back for getting through it."

"Every relationship you have, you're learning and growing and taking something from that," Lively previously explained to Glamour of their break up. "So for me, it's never been too dramatic of a thing when something ends."

"We haven't spoken in a while, you know," Badgley told the Huffington Post back in March 2015. "There's an amicable silence if that makes any sense."

We will continue to update this story.