Bradley Cooper has been warming up to the idea to propose to his model girlfriend Suki Waterhouse, a source exclusively tells Us Weekly -- get the details Credit: David M. Benett/Getty Images for The Serpentine

Sorry Betty White!

Bradley Cooper and Suki Waterhouse may be taking the next step in their relationship, Us Weekly can exclusively reveal. An insider tells Us that the model is itching for an engagement ring.

"Suki says she's been warming him up to the idea of marriage and he's starting to get excited about it," the source tells Us. "It's up to Bradley to pop the question, of course, but she hopes it happens soon."

The American Sniper actor, 40, and Waterhouse, 23, began dating in March 2013, and made their first Hollywood appearance together at the star's American Hustle NYC premiere that December. (Cooper was previously married to actress Jennifer Esposito from December 2006 to November 2007.)

Waterhouse also has babies on the brain. "I really like the idea of having kids in not too long. Not, like, now. And not next year. But in not too long," she told Elle UK in December 2013.

She added of Cooper: "Look, maybe it's best for me to say, 'I'm not one of those girls who goes on about their boyfriends.' I do think whatever I say will sound weird. But the truth is, if I start talking about him, I probably won't be able to stop. And I don't really want to talk about him, you know?'"

Someone she may gush to about Cooper? His mom Gloria! "They hang out when Bradley is busy," the source says. "She wants Gloria to know she's in the relationship for the right reasons."