Williams was beaten in the final in straight sets by Angelique Kerber last year but can seal a record-equalling 24th Grand Slam title with victory on the grass in SW19.
Halep is into the final of Wimbledon for the first time in her career but has a poor record against Williams and has won just one of 10 meetings between the two players.
Date: Saturday, July 13
Time: 2 p.m. BST/9 a.m. ET
TV: BBC (UK), ESPN (U.S.)
Wimbledon Women's Final Preview
Williams goes into Saturday's final as the favourite for victory and has grown in strength as the tournament has progressed.
The 37-year-old arrived at the All England Club short of match practice after struggles with a knee problem but has not looked troubled by the injury and has shown few signs of rustiness.
The American has enjoyed plenty of game time on the grass in London. She has also played mixed doubles with Andy Murray, reaching the third round before being beaten by top seeds Bruno Soares and Nicole Melichar.
Six-time Wimbledon champion Billie Jean King feels playing mixed doubles has helped Williams:
The 11th seed did drop a set each against Slovenia's Kaja Juvan in the second round and Alison Riske in the quarter-finals but has otherwise been untroubled in wins over Carla Suarez Navarro, Julia Gorges and Guilia Gatto-Monticone.
The former world No. 1 was also in dominant form to crush unseeded Czech Barbora Strycova in the last four in 59 minutes:
The American is into the Wimbledon final for the 12th time in her career and victory will see her equal Margaret Court's record for Grand Slam wins:
Williams has an outstanding record against Halep but has not forgotten the one defeat she suffered against the Romanian at the WTA Finals in 2014:
Ben Rothenberg @BenRothenberg
Serena cites loss at 2014 YEC (6-0, 6-2) for her record vs Halep (9-1) "The biggest key with our matches is the loss that I had. I never forgot it. She played unbelievable. That makes me know that level she played at, she can get there again. So I have to be better than that."
The seven-time champion is yet to win a title since returning to the tour from maternity leave in March 2018 but is now into her third major final since her comeback.
Williams has wobbled in finals while chasing her 24th Grand Slam. She was beaten comfortably by Kerber at Wimbledon last year and tasted defeat to Naomi Osaka at the 2018 U.S. Open but looks in strong form for her third attempt.
Meanwhile, Halep has told reporters she is "desperate to win Wimbledon" after booking her place in the final after a straight-sets win over eighth seed Elina Svitolina.
The seventh seed has won all but one of her matches at Wimbledon in straight sets, beating two-time Australian Open champion Victoria Azarenka, China's Zhang Shuai and ending the hopes of 15-year-old Coco Gauff:
Halep has struggled in the past at Wimbledon, losing in the first round in 2012 and 2015, but has looked at home on the grass this time around:
The 27-year-old also does not appear daunted at the prospect of facing Williams at Wimbledon, per Katie Falkingham at BBC Sport.
"I will believe that I have my chance to win against her. Of course, I respect a lot what she has done and what she's doing. But now I feel stronger mentally facing her. We will see what is going to happen. It's just a big challenge for me."
Halep was beaten by Williams in three sets at the Australian Open in January in an intense match that lasted nearly two hours at the Rod Laver Arena.
The Romanian is playing arguably the best grass-court tennis of her career at Wimbledon and will pose Williams a threat, but the seven-time champion will take some beating and looks in great shape to make more history on Saturday.