'Heartbroken' Connie Britton mourns 'Nashville' costar Hayden Panettiere's tragic death

Connie Britton is heartbroken over the sudden death of her Nashville costar Hayden Panettiere.

Taking to her Instagram handle on Monday, the 59-year-old actress expressed her grief over the tragic death of Hayden.

“This was Hayden. Bursting with brilliance, shining so bright,” Connie penned. “I have no words for this sad song. Just heartbreak.”

“I love you girl. Sleep easy now," she added.

Connie and Hayden acted together in Nashville for five seasons.

For those unversed, Hayden passed away on Sunday, August 16. Her dad, Skip Panettiere, announced the heartbreaking news.

“It is with profound sadness that we share the tragic passing of our beloved Hayden," he said in a statement to ABC News.

"She was an incredible light and a force of nature who brought immeasurable love and joy to all who knew her — and to the millions who watched her onscreen,” Skip continued.

The actress' father also asked for privacy “as our family takes time to process this unimaginable loss."

It is worth mentioning here that Hayden appeared in several projects throughout her entertainment career. However, she rose to fame after starring as cheerleader Claire Bennet in the sci-fi film Heroes.