The finale of The 100 will air as a two-part episode on 4 March and 11 March at 9pm on The CW.

Click here to watch the two-part finale online on the CW website.

The finale is titled, Blood Must Have Blood, and the synopsis of part one reads as follows:

Clarke (Eliza Taylor) and Lexa (guest star Alycia Debnam Carey) prepare for battle, while Raven (Lindsey Morgan) and Wick (guest star Steve Talley) experience a major setback. Meanwhile, Octavia (Marie Avgeropoulos) and Lincoln (Ricky Whittle) are each forced to make a difficult decision. At Mount Weather, Jasper (Devon Bostick) and Maya (guest star Eve Harlow) witness a horrible act, Bellamy (Bob Morley) follows through on a promise and Cage (guest star Johnny Whitworth) goes public with powerful information.

The synopsis of part two of the finale reads as follows:

The journey to the City of Light continues, and Jaha (Isaiah Washington) makes a move that shocks Murphy (guest star Richard Harmon). Clarke (Eliza Taylor) receives help from an unexpected source, a visitor surprises Octavia (Marie Avgeropoulos), and Lincoln (Ricky Whittle) gets his revenge. Meanwhile, at Mount Weather, Cage (guest star Johnny Whitworth) moves forward with his mission and Bellamy (Bob Morley) and the group struggle to break free.

In the last episode we saw Lexa, Clarke and company on their way to besiege Mount Weather. The mountain's acid fog is successfully disabled thanks to Bellamy's efforts, but the battle is far from won.

New spoiler photos from the 4 March episode have been released, showing the Commander's army preparing for war.

Meanwhile, writer Aaron Ginsburg also teased an explosive season finale.

Last week's episode featured a sudden lip-lock between reluctant partners Clarke and Lexa.

"For a while, one of the main characteristics about Lexa was that love was no longer an option for her, so I figured it was never going to happen," Alycia Debnam Carey, who plays Lexa told TVLine.

"The writers would put sly little suggestions in the script every now and then, but both Eliza [Taylor] and myself were like, 'No way, it's not going to happen.' Then we finally read this past episode and went, 'OK, it really is happening!'

The actor also teased a battle ahead and said, "They're about to go battle, which is the most important thing right now for both characters.

"It's what they've been working towards all season; as for anything else, we'll have to wait and see," Debnam Carey concluded.

Watch the promos here: