Stars Goin' All Out for Valentine's Day ... Love Is in the Air!

Love's in the air ... and, Hollywood isn't immune to Cupid's Arrow -- 'cause tons of them are breaking out flowers and balloons, and even striking their sexiest poses for Valentine's Day.

Take Bella Thorne, for example ... tossing a smolder to the camera while showing off her bodacious backside in a tight red dress. Meanwhile, Summer Walker looked angelic in an all-white outfit while planting a kiss on her man, Rico Recklezz.

Model Olivia Ponton shot her sexiest look at the camera too ... tongue out and winking with a candy heart resting on her tongue.

While some celebrities are all about sex appeal, it's worth noting others are celebrating with their kids ... like Khloe Kardashian, who bought custom balloons to celebrate her little ones, and Halle Bailey, whose son is celebrating his second Valentine's Day.

Charlie Puth looked covered in love for the holiday ... and, we mean that literally 'cause the music star was covered in a series of red lipstick smooches -- from his face down his shirt.

And, Karin Jinsui proved she's pretty in pink ... shacking up with a bright pink teddy bear -- and wearing a matching pair of lace lingerie.

There are a ton more celebs celebrating too ... and, ya gotta click through the whole gall to see how Hollywood's celebrating the loved-up day.

And, if you get caught up in the gallery and run out too late to get a Valentine's Day card for that special someone -- don't fret! We've got some cute custom cards just for you!