The 28-year-old has not played since his tied for 21st finish at the Commercial Bank Qatar Masters in March but his opening round at The Celtic Manor Resort was well worth the wait.
Pieters became a father for the first time to daughter Florence during the four month hiatus caused by the coronavirus pandemic and he also donned a longer hairstyle on his return - with plenty of people, including his partner, citing similarities to Tommy Fleetwood.
And the four time European Tour winner had more to celebrate as he came home in a stunning 29 to take the outright lead by one shot over early clubhouse leader Toby Tree at seven under par.
Pieters carded the only bogey of his round at the second but had to wait until the sixth to pick up his first shot and nudged to one under with a birdie at the next.
However, it was on the back nine when the Belgian soared into contention as he started with back to back gains at the tenth and 11th to get to three under.
He rolled in from six feet for birdie at the 14th before holing another at the next from ten feet to sit one shot behind Tree and Swede Sebastian Soderberg at the top of the leaderboard.
Soderberg jumped ahead to seven under at the 15th courtesy of his eighth gain of the round but Pieters joined Tree after a terrific chip in from the rough on the par three 17th following a wayward tee shot.
Moments later, Soderberg dropped a shot at the 16th to make it a three way tie for the lead at six under but when Pieters chipped to within two feet at the last and rolled in for a birdie, he took the outright lead.
The Swede, playing in the group behind Pieters, then found water with his approach into the par five 18th and could only record a bogey as he dropped to five under, one behind Tree sat in solo second.
Earlier in the day, Tree continued his momentum from a top 30 finish at last week's English Championship with an opening birdie, only to record his sole bogey at the second.
But he trended upwards thereafter with a gain at the fifth before picking up successive shots at the eighth and ninth.
Another birdie at the 11th moved him clear at the top at four under and when he carded a three at the par four 15th, his lead extended to two shots.
Soderberg, Australian Min Woo Lee and Belgium's Nicolas Colsaerts closed in to within one shot of the leader but Tree restored his two stroke advantage with his seventh birdie of the day at the par three 17th for a six under par 65.
Italian Edoardo Molinari, who was part of Team Europe's Ryder Cup winning team at this venue ten years ago, was in the clubhouse alongside Soderberg at five under, while American Sihwan Kim was at that mark through ten holes.
Colsaerts carded 67 despite back issues during his first round, with Dutchman Wil Besseling also at four under with two holes to play.