Robert Pattinson and Suki Waterhouse have sparked engagement rumors after Waterhouse was seen wearing a ring on her left hand.

The actor, 37, and his actress/model girlfriend, 31, were seen walking around London on Monday in photographs published by TMZ.

The engagement speculation comes after Waterhouse revealed she is pregnant while performing onstage at last month’s Corona Capital Festival in Mexico. In a fan-captured video posted on X (formerly Twitter), she addressed her glittery pink outfit, telling the audience, “I’m extra sparkly today because I thought it might distract you from something else that’s going on.”

She then opened the feathery coat she was wearing over her formfitting minidress to reveal a baby bump, prompting cheers and applause from the crowd. “I’m not sure if it’s working,” she jokingly added.

A week later, a source told PEOPLE she and Pattinson are “thrilled” about having their first child on the way. “A baby coming is an absolute joy for them,” the source said of the couple. “They are thrilled beyond words.”

Another source added, “They are ready for a child, and looking forward to becoming parents. Even though they are both professionals who work a great deal, this is something they want. They know their lives will change, and they are excited.”

Pattinson and Waterhouse first sparked romance rumors in 2018 when they were spotted showing PDA in London. A source later confirmed to PEOPLE that they were indeed dating.

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The Daisy Jones & The Six actress and Twilight alum have been relatively private since they began dating and have only discussed their relationship a handful of times throughout the years.

When asked about his relationship by The Sunday Times in 2019, Pattinson said, “If you let people in, it devalues what love is.”

“If a stranger on the street asked you about your relationship, you’d think it extremely rude. If you put up a wall, it ends better,” the actor added.

The couple recently made their red-carpet debut, attending the Dior Men Fall 2023 show in Giza, Egypt, in early December, where they walked arm-in-arm and exchanged loving glances.

Pattinson also discussed the experience of watching The Batman next to Waterhouse in a February 2022 interview on Jimmy Kimmel Live!.

“I’m pretty sure she’s not normally into watching superhero movies,” he explained to host Jimmy Kimmel. “And just seeing that it was capturing her attention the entire time, and then she held my hand and touched it [to her face] and I could feel a little tear. And I was like, ‘No way!’ “

The upcoming marriage will be the first for both Waterhouse and Pattinson, the latter of whom previously dated his Twilight costar Kristen Stewart and, later, was engaged to FKA Twigs after dating for more than two years.

Waterhouse dated Bradley Cooper for two years until their breakup in the spring of 2015 and, shortly after, dated Diego Luna until 2017.