SANDRA BULLOCK and Chelsea Handler are bat­tling for the affections of a younger man – 33-year-old “Captain America” hunk Chris Evans!

At 39, Chelsea is six years older than the big-screen beefcake – and sources say the late-night talk host thinks that gives her an edge over 49-year-old Oscar winner Sandra.

“Sandy and Chelsea both fell for Chris at the same time,” said a source.

“Chelsea assumed that Sandy wouldn’t go for Chris because he’s so much younger, but Sandy is telling Chelsea to back off. Sandy thinks she should get first dibs on Chris because she hasn’t dated in ages, and she’s ready for a hot hookup!”

But Chelsea isn’t giving up without a fight, said the source.

“Chelsea reminded Sandy that she’s old enough to be Chris’ mom, and a romance with him could make her the laughingstock of Hollywood,” said the source.

“Fantastic Four” star Chris dated Jessica Biel, 32, for two years and was most recently linked with actress Minka Kelly, 33.

But after meeting “Gravity” beauty Sandra in early 2012, Chris gushed: “I used to be in love with Sandra Bullock when I was growing up. Sandy B. was my girl. I remember seeing ‘Speed’ when I was in seventh grade and just thinking, ‘That’s her.’”

Flash forward to April when the “Avengers” stud sat down for din­ner with Sandra, Chelsea and “Bridesmaids” cut-up Melissa McCarthy at West Hollywood hot spot Craig’s.

Then, in early May, Chris got together again with Sandra and Chelsea at another West Hollywood eatery, Cecconi’s.

After that, “Chelsea ad­mitted to Sandy that she was bowled over by her incredible chemistry with Chris and was falling for him,” said the source.

“That’s when Sandy told Chelsea that she and Chris were the ones making sparks. And they’ve been bickering like school­girls over him ever since.”

Unlucky-in-love Sandra – who once dated 16-years-younger Ryan Gos­ling – has been single since her 2010 divorce from cheating ex Jesse James.

As The ENQUIRER reported, she was crushed by her longtime pal George Clooney’s engagement to gorgeous lawyer Amal Alamuddin, and equally devastated when Ryan Reynolds, her 12-years-younger co-star in “The Proposal,” married blonde bomb­shell Blake Lively.

Meanwhile, Chelsea – who split from hotelier Andre Balazs last fall – is notorious for ruffling celebrity feath­ers. As The ENQUIRER has reported, she’s tangled with Angelina Jolie, “To­night Show” host Jimmy Fallon and even her long-time BFF, Jennifer Aniston.

“Chris has been call­ing Sandy and sending her flowers, but Chelsea won’t back down,” said the source.

“Chris is trying to avoid the drama, and he doesn’t want to incur Chelsea’s wrath by flat-out rejecting her.

“But someone’s going to come out a loser – and it will probably be Chelsea.”