“As the person who had a front row seat then?

This wasn’t it,” Burton wrote on social media.

Hilarie Burtonis standing up for her longtime friendSophia Bushamidmessy cheating rumors.

Hilarie Burton and Sophia Bush; Chad Michael Murray and Erin Foster

Hilarie Burton and Sophie Bush; Erin Foster and Chad Michael Murray.Shane Gritzinger/FilmMagic; Frank Trapper/Corbis via Getty Images

“As the person who had a front row seat then?

This wasn’t it.”

Now this is being spun to make my sister look like a brazen harlot.

And if she’s anyone’s harlot, it’s mine!"

Tagging Foster in the post, Burton wrote that she was “happy to discuss” the issue.

“You also deserve truth,” she added.

I’ll be a named source.

Lotta internet voices being nasty, and as the person who knows the real timeline?

It would be laughable if it wasn’t so hurtful."

A representative for Foster didn’t immediately respond to EW’s request for comment Monday.

A rep for Burton declined to comment further.

They were granted a divorce the following year.

Last week, Foster and her sisterSaradiscussed relationship gossip on their podcast,The World’s First Podcast.

“I mean, yeah.

“While we were living together.

Murray and Foster started dating in 2001.

I’m over it now.

I mean, just barely.

Just barely over it.”