Jessica Biel and Katie Holmes have been married to two of the hottest men in Hollywood. So it's no wonder that the brunette beauties had plenty to talk about when they caught up at the Tiffany debut of the 2014 Blue Book on April 10 at the Guggenheim Museum in NYC.

Rocking very different looks, Biel took the plunge in a low-cut Oscar de la Renta gown, while Holmes played it more casual in a thigh-high mini by Balenciaga. We loved both looks, but this time the win goes to JT's wife, who has been acing countless appearances without her husband in recent months.

Katie Holmes, Jessica Biel and Kate Bosworth Gorgeous x 3! Whether going short or long, Katie Holmes (in Balenciaga), Jessica Biel (in Oscar de la Renta) and Kate Bosworth (in Kate Ermilio) all dazzled at Tiffany's Blue Book Gala at the Guggenheim Museum in NYC.

Biel and Holmes actually have a lot more in common that you might think. Both actresses got their starts as teens in family-oriented dramas that ran on the WB around the same time. Biel's show, 7th Heaven, was on from 1996 - 2007. Holmes' series, Dawson's Creek, lasted from 1998 - 2003.

At 32, Biel is a little bit younger than Holmes, who is 35. But they won us over on-screen at the same time. They also married men whose careers were — and are — huge.

Biel and Holmes aren't the only celeb BFFs who might surprise you. Whether partying or exercising together, these friends have seen each other through thick and thin:

1. Julianne Hough and Nikki Reed

Maria Menounos, Derek Hough, Nikki Reed and Julianne Hough Selfie, anyone? Maria Menounos, Derek Hough, Nikki Reed and Julianne Hough couldn't stop laughing as they took selfies and checked out one another's gowns at The Kaleidoscope Ball –in Beverly Hills.

There's a reason that Hough and Reed are in such great shape. They constantly work out together! Recently the two stunners even went from the gym to a hiking trail with Reed's dog Enzo.

2. Cameron Diaz and Leslie Mann

Kate Upton, Cameron Diaz and Leslie Mann Stunning x 3! We get why a man couldn't decide between Kate Upton, Cameron Diaz and Leslie Mann. At the London premiere of 'The Other Woman' each blonde outshined the next.

It's not a coincidence that Cameron Diaz and Leslie Mann are holding hands. They got extremely close when filming their new movie The Other Woman!

3. Beyonce and Gwyneth Paltrow

Beyonce and Gwyneth Paltrow Pictured here at the 2007 Oscars, Beyonce and Gwyneth Paltrow have remained close friends for years. Both part of power couples involving a huge musician, they always had much to talk about.

Beyonce and Gwyneth Paltrow were both married to two of the most successful musicians in the world. As a result, they've always had a lot to talk about.

4. Taylor Swift and Karlie Kloss

Taylor Swift and Karlie Kloss Meet new BFF's: Taylor Swift and Karlie Kloss!

Though Victoria's Secret model reportedly thought Taylor Swift was stuffy when she sang at the annual show, VS stunner Karlie Kloss took an instant liking to the country crooner.

5. Katy Perry and Allison Williams

Katy Perry and Allison Williams Katy Perry and Allison Williams didn't meet at the 2013 Grammys, they've been closed friends for years!

When Katy Perry was dating John Mayer, Allison Williams would take hikes with them. Gushing about the "Roar" singer, Williams said: "Talk about someone who wears it lightly. She’s the most followed person on Twitter and still somehow has time to ask, 'So, how did the photo shoot go?'"

Now that's impressive.