Mandy Moore has lead tributes to 'This Is Us' writer Jas Waters after she died at the age of 39.

The screenwriter's passing was confirmed by the writing team's Twitter account on Wednesday (10.06.20) afternoon, but it is not currently known how she died.

The ThisIsUsWriters account posted: ''The entire #ThisIsUs family was devastated to learn of Jas Waters passing. ''In our time together, Jas left her mark on us and ALL over the show. She was a brilliant storyteller and a force of nature. We send our deepest sympathies to her loved ones. She was one of us. RIP @JasFly.(sic)''

Mandy - who plays family matriarch Rebecca Pearson in the drama series - took to her own Twitter account to share a message of sympathy.

She wrote: ''Sending love and light to @JasFly's family and loved ones.''

Her co-star, Susan Kelechi Watson - who plays Beth Pearson - was ''shocked and saddened'' by the news.

She wrote: ''Incredibly shocked and saddened to have just receive this news. Blessed Light, fly with the angels.''

'This Is Us' creator Dan Fogelman praised Jas as a ''brilliant'' writer who would be very much missed.

He wrote: ''This news took my breath away. Jas was absolutely brilliant and had so many stories still to tell. She made an indelible mark on our show and my heart breaks for her loved ones. RIP @JasFly.''

'Insecure' star Issa Rae also paid tribute to ''generous, beautiful and real'' Jas.

She tweeted: ''''I'll never forget being so excited to get an interview w/ @JasFly for Necole Bitchie back when I was working on ABG. I could feel her warmth through the phone. Over the years, I got to know & appreciate her even more. She was so generous, beautiful and REAL. I'll miss you, girl.(sic)''

And 'Glee' star Amber Riley hailed Jas as an inspiration.

She wrote: ''I can't believe I woke up to hearing you are gone @JasFly. You inspired me so much and challenged my thinking also. I truly admired you as a writer and just as a black woman. We never got to work together like we wanted, but I'm so glad to have known you. #RIPJasFly.(sic)''