CBS hit sitcom "The Big Bang Theory" has their own Ross and Rachel of the 10-season NBC sitcom Friends, according to some viewers.

Leonard (Johnny Galecki) and Penny (Kaley Cuoco), who make the first romantic couple of the comedy series, are not really okay at the end of Season 5. (Warning: Spoilers ahead)

Leonard pops the let's-get-married line to Penny in bed. She is absolutely pissed that he would do such a thing in the bedroom. Then she goes on to deliver a wedding speech about the location not being an issue when two people are really in love. (She's got burned, says Sheldon Cooper.)

They are officially dating again for the second time and after some weeks of "alpha test," Leonard decides it is time to bring their relationship to the next level. She has daydreamed of marrying him - but only 'cause in her daydream version, she was knocked up. Yet, she is flustered by the manner in which he proposes - as if she is ready for the same kind of proposal in a different setting. (But is she?)

Just another Ross and Rachel?

TBBT fans could not help but notice how the dynamics of Leonard's and Penny's relationship are similar to how Rachel and Ross went on again and off again in the legendary sitcom. To begin with, Rachel was a waitress (but she became a fashion line executive later on) and Ross, a scientist.

Will the audience actually see a pregnant Penny sometime in the future?

"Before you know it, Penny will be having Leonards' baby, then thinking she's in love with Raj, then it'll be back to Leonard," a reader laments.

"My goodness just get her pregnant already!" Another news commenter says.

On Friends, waitress Rachel (Jennifer Aniston) and paeleontologist Ross (David Schwimmer) got together by the second season, but broke up in the third season. They never really officially reconnected until the final episode of the series. Yet they had a baby in Season 8. And they had always been Rachel-and-Ross, even when Rachel fell in-love with Ross' bestfriend Joey (Matt LeBlanc) for a while.

Meanwhile, both Galecki and Cuoco have expressed hope that their characters will still end up with each other. Their answers hint, however, that it's not going to happen anytime soon.

Speaking to Digital Spy at last month's Comic-Con, Galecki said Penny "has some emotional maturing to do." Cuoco mused, "I feel that down the line I'd love to see them together - maybe not right now, but down the line."

The TBBT fans could only hope for a more creative approach on the Leonard-Penny arc, so that it could be as original as possible, away from the shadows of Rachel-Ross.

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