Liam Payne wants to "prove he's worthy" of Cheryl Fernandez-Versini.

A source said: "Liam has fallen hard for Cheryl.

"At first, he was overwhelmed by all the drama - especially her divorce - but after everything they've been through, he's so head over heels in love with her and he's being very protective.

"He's always trying to please Cheryl and trying to prove to her that he's worthy of being her boyfriend, in the sense that he's so young and was always afraid that she might not take him seriously.

"He's always showering her with gifts, acting like a loved-up puppy dog and planning their future together."

However, Cheryl's mother, Joan Callaghan, has warned the 'Fight For This Love' singer - who was also previously married to Ashley Cole - not to rush into another serious relationship.

The source told heat magazine: "Her mum Joan has sat her down and told her to take things slow, and that if something is right, it will wait.

"Cheryl is a real romantic at heart, but at the same time, she needs to be sure about what she's getting into.

"She's already been married twice and rushed it with JB, and I think everyone is hoping she won't do that again, even though Liam is a really good guy.

"She can blow hot and cold on the subject of their future together and that could be confusing to Liam."

Meanwhile, Liam recently gushed that he thinks Cheryl, 32, is "amazing".

The couple - who have been dating for three months - made their red carpet debut together at the Global Gift Gala in Paris, France, earlier this month when the 'Only Human' singer received the Global Gift Philanthropist Award and the One Direction hunk couldn't be more proud of his girlfriend.

He said: "It's her night and I'm very proud of her. She's amazing."

And when asked how her relationship is going, Cheryl smiled and said: "I am just very happy."