The 'Game of Thrones' star and the Jonas Brothers singer are yet to comment on the news.
Meanwhile, it was recently reported the 24-year-old actress "can't wait" to become a first-time mother.
A source said last month: "Joe and Sophie are excited to be new parents and have been enjoying the process of getting ready for their baby. Sophie and Joe have been trying to also stay active going on walks and hiking."
"The whole Jonas family is looking forward to showering the new addition with love. Sophie is due soon and can't wait to be a mum."
Sophie previously admitted she is "loving" being in quarantine at home with Joe amid the coronavirus pandemic - but he feels like he's in "prison".
Speaking about their time in lockdown, she said: "I'm kind of loving it. I'm an introvert, I'm a homebody, if I could stay at home all day I would, so this is great for me.
"I see how people are finding it difficult, but I don't understand how people are really struggling to practice social distancing. I'm like, all you have to do is stay at home and get drunk at home."
"It's great. Joe and I. .. everything seems to be working out in my favour here because Joe is a real social butterfly and I struggle to lock him down and just spend time with me. It's like a prison for him, but it's great for me."
"However, Sophie was keen to support her spouse by bringing the 30-year-old star tequila shots during his sessions when he texts her asking "what time is it?"
She quipped: "There's no rules in quarantine."