Lots of celebrities have admitted to watching The Bachelor in the past (we're looking at you, Jennifer Aniston) — but we never thought Sean Penn would reveal he's a fan of the show!

During an appearance on 'Jimmy Kimmel Live,' the 54-year-old actor confessed he and his girlfriend, Charlize Theron, 39, loved watching the latest 'Bachelor' and are gearing up for the upcoming season of 'The Bachelorette'!

"Britt or Kaitlyn?" the 'Milk' star began the conversation, referring to Britt Nilsson and Kaitlyn Bristowe, the newly announced 'Bachelorette' duo. (Both ladies will be looking for love on season 11 of the hit ABC reality show.)

sean penn and jimmy kimmel

Sean and Jimmy on 'Jimmy Kimmel Live!' on March 12, 2015.

"Oh interesting, wow you're a 'Bachelor' fan? I never would have guessed this! Oh my godness, my head just exploded," a shocked Jimmy, 47, responded to Sean's inquiry.

"Do you and Charlize watch 'The Bachelor'? I assume you're watching with her, or else, if you're watching it alone this is real weird," the host asked.

Related Story: Sean Penn Disses Madonna and Robin Wright: 'Charlize Theron Would Be My First Marriage'

"We argue about whether or not we should fast [forward]," revealed Sean, who was on the show to promote his new movie, 'The Gunman.' "I don't really want to hear the conversations, I want to know the decisions. You can decide on this one or this one. And I want to see somebody cry. And then see somebody get ecstatic and then see them cry."

'the bachelorette'

Season 11 Bachelorettes Kaitlyn (left) and Britt (right). (Photo Credits: Getty Images)

Jimmy then asked the father-of-two whether he would be rooting for Britt or Kaitlyn to win over the hearts of the 25 men competing on the new season of 'The Bachelorette,' which premieres Tuesday, May 19.

"It's going to have to be Kaitlyn," Sean coyly replied during the Thursday, March 12 interview.

Watch Sean admit to being an avid 'Bachelor' fan in the video below!